Waiting for a diagnosis...am I overthinking the whole situation?

Hi. I'm not sure where to begin. I (f18) have recently reached out via my sixth form, to ask my form tutor about potential referral for ASD screening as I believe I might have Asperger's/be on the spectrum. A few years ago, when I was 14, a psychologist I talked to about generalised anxiety disorder noticed some patterns and problems in my social communication abilities and recommended I get screened, but, having a very preconceived, uneducated view of the low functioning autistic male stereotype, I pushed it aside and rejected it. 

Now, having done some research into autism and particularly how it presents in girls, I'm wishing I hadn't.

Ever since I was in primary school or even earlier, I've felt different and unable to put my finger on quite why. I had difficulties which were much more marked back in primary - from meltdowns in school when I got told off for little things, being told off for making inappropriate facial expressions/using the wrong tone of voice, to a huge special interest in reading/writing and difficulty maintaining friendships or being able to gauge people's intentions/when they were joking or making fun of me. I also found it impossible to work in groups. For as long as I can remember, I tap the bed with my foot at night to burn off excess energy and often to calm me down, and I only recently recognised this as a form of stimming (amongst others). 

I've had family problems and all the arguments that used to happen between my parents sent me into constant meltdown with extreme stims like hitting myself. Now I live by myself because I find it physically hard to be around my mother for more than a few minutes without losing my temper with her. I recently had a really bad meltdown that resulted in me smashing a window as I felt so ignored by her.

I've been through multiple periods of bad mental health as a teenager, from an eating disorder that was marked by an extreme obsession with routines and rituals (to the point where, even with improved body image, I was still conforming to some of my previous behaviours and unable to break out of them without a lot of anxiety), to what I thought was social anxiety as I had such trouble interacting with others, to - over the past 3 years - about six or seven periods of burnout that often took weeks to fully recover from. 

My most recent burnout was in November, and I'm still only recovering now. I was extremely anxious for weeks on end, my executive functioning was at an all time low - normally I love music and take pride in doing well in my schoolwork, but I found it impossible to do even the little things like getting out of bed. I was self-isolating at the time and extremely agitated from being unable to leave the house; pacing (one of my main stims) almost constantly, having pretty much daily meltdowns, and then when my isolation period ended, I literally couldn't be on my own so my boyfriend had to be at my place virtually all the time to look after me physically and mentally. 

Around the age of 15-16, I really thought I had dysthymia. I felt like there was a brick wall between me and my "friends", like they would never understand me, and constantly had to withdraw socially to cope.

I've had troubles with relationships and maintaining friendships, you name it, I'm also hypersensitive but more so to temperatures, as well as to physical sensations, changes and pains in my body which can sometimes send me into overdrive (hypochondriac). I used to be an extremely fussy eater as a child and going to restaurants was impossible because of it, but ever since going vegan, my diet has become much wider and more flexible, as many of the foods whose textures, tastes etc distressed me were meat.

Despite all this, I keep self-sabotaging and telling myself my problems are invalid! I keep thinking back to times when things went well for me socially, like when I did NCS in 2019 and got on well with a few new friends, like the fact that I now have a stable, happy relationship and a best friend (I don't feel the need for more than 2-3 friends as maintaining more friendships than this is absolutely exhausting for me). I feel as though I'm not affected enough by sensory overload to have an autism diagnosis - sometimes when I'm really stressed I get really affected by small sounds and I can't sleep at night without complete darkness and silence, but I'm not really affected by large crowds if I'm with someone else, and I find concerts really relaxing (as long as I'm at the front not in the mosh pit!) as music is a passion of mine.

I'm so sorry about how long this is. I'm bad at cutting things down (autistic trait?) and always go into too much detail and overshare. Low down is:
Is this all in my head? Am I making it up as my social skills are so much better in certain situations now than they used to be and I have managed and sometimes enjoyed or got oddly hyperactively enthusiastic about social get-togethers with people? 

Do I deserve a diagnosis or am I going to be shut down straight away?