Progressed/Gained A Lot Of Experience Recently At Work But Not Sure If I Am Being Valued/Noticed?

So I have now nearly worked for this firm for 6 years. During my time working there, I was able to learn various different basic admin/accounting tasks from my line manager but we both knew this I guess we rarely ever had good communication with each other, we got on well with random talk non work related but when it came to work related stuff, he noticed it more and more that when he was trying to explain something to me on how to do a task etc, I never am able to understand it and I have really a lot of trouble processing the information that he explains when I'm taking it in. I think he knew I struggled a lot but the tasks which I have understood, I have done them all very well and my line manager can see from this and I think he knows this. I had discussions with my line manager before about how grey areas I really do struggle with and I'm a bit better with them now I think but at the time I just can't help it I think it is to do with my aspergers as well only being able to understand tasks with a set routine/ done in the same way (I have loads of notes now about how to do various different tasks now as I found that this helps me a lot as I tend to forget things easily)

Just about a few months ago, during my apprasial, my line manager said to me that he'll get someone else in to be able to assist me so we can move the department on and be able to organise things a bit better and because they'll assist me, they will do some of my tasks too and my line manager did say that I can then expand on my role and learn more etc. It is sort of true now but because the other persons a apprentice, we often just learn the same thing at the same time together (me and him) when my manager is showing him stuff etc. I taught the apprentice all of how to do the basic accounting/admin tasks but then something unexpected happened and after working for the firm for about 30 years now, my line manager found a better paid job and he was due to leave and just recently left. But before he had to leave, someone had to take over his jobs what he's doing, we had a few months to prepare the training etc, he taught me and the apprentice some of the tasks what he done but taught the apprentice the additional extra tasks what which didn't involve me which is fair enough because he did explain to me that it's better teaching him than me because he is doing the qualification and has better knowledge/understanding etc (I never did that qualification) So then during near the last days my line manager is leaving, he started to teach me less and less stuff and I got gradually less and less involved with what he does, He was just facing the apprentices direction and said to him about the various jobs and everything and what to look out for etc, he passed me the key to something in the building, but decided to give the apprentice the key to get in the building etc and not me, gave the apprentice the login passwords and not me, and he said that I was the manager know and the apprentice is my assistant in a joke sort of way. I don't like confrontation and to ask questions/complain etc so that's why I didn't say anything why I didn't get the key for the building instead. Also, when I was just continuing working, during the last few days before my line manager was due to leave, (we were all stressed about another thing what happened in our department recently) he went out for 5/10 minutes with the apprentice and kept letting me know that they're going out for a *** and if I will be ok on my own for about 5 minutes, I always agree and I just get on with it but I have no idea what they're talking about and if they were actually talking about me not being able to understand things quicker than my apprentice probably? They went out doing the private talks for at least 4/5 times again without me being involved with anything after I have been working there for nearly 6 years. But I didn't complain, I just got on with it and done as I'm told. Now my managers left, first thing when I got in today, apprentice is in my line managers desk now he moved there (Although my manager did ask if I wanted his desk a while ago because he said to me that I am the most senior after he's gone and I said that's ok I'll stay on my own desk) so that's fair enough with the desk thing but it still hurts me with all these things building up now.

The managing partner even everything always asks the apprentice to do the higher important tasks for him and never asks/involves me either now that my managers left. They had a interview, again I wasn't even asked to go in and get involved, the managing partner asked the apprentice to go in with him instead to the interview. There's loads of various other things as well like every other staff always asks the apprentice about a query instead of me etc. It feels like I'm invisible and not even there? Could it be because they know how I'm like cos my line manager told the the other staff that I don't like communication (Which I don't tbh) and I have difficulty understanding and taking in information and they think that I won't be able to handle all the responsibility or is it because it actually helps with my aspergers to keep the routine the same and I have been doing more higher up tasks now and got a lot more responsibility but it's always just a but annoying in a way it hurts that I feel like for all the time I've been working there and the apprentice has only been working there for a few months, he gets way more responsibility/tasks than me and to not even give me the key in the building and choose the apprentice over me instead, I am not sure how I should feel about this? Why are they doing this because I guess most aspies, I don't understand the purpose and intention and what they're thinking and it's making me anxious/annoyed and maybe jealous perhaps?

I don't know if I should change jobs I really don't want to because it will just mean starting from scratch again and re learning everything. Oh and also the apprentice is in contact with my line manager a lot asking him about how to do the tasks, they kept texting again me not even involved which is fair enough as well as my line manager does know my various difficulties etc Because I suffer from OCD, anxiety as well (they don't know that) I think I have depression as well and this just made me even more upset.

The apprentice picked up how to do new tasks way quicker than me and he knows more as well of how accounting works etc. But he does treat me with a lot of respect as well and he is very nice to me so that I am happy about. I'm just upset about all the other things which has happened and that why they always treated me like i'm the assistant now. I won't say anything to be honest I'll just get on with it but I am just depressed and upset over this I needed somewhere to get these feelings out.