Burnout / repeated meltdowns - trigger warning (suicidal thoughts)

Firstly, sorry this is probably going to break the forum record for the longest post ever written! Thanks in advance to anyone who manages to read it all. There is a brief mention of suicide in this post - mods, please add trigger warnings / edit etc if you need to, I've put one in the title.

Before my autism diagnosis I have been diagnosed with so many different mental health and physical health conditions including chronic fatigue syndrome (since age 16, 20 years ago), ibs (age 18), depression and anxiety (age 22), bipolar - (age 28), fibromyalgia (age 32), Borderline Personality Disorder (age 35). I also have type 1 diabetes and at long last an ASD diagnosis. I now know that I'm definitely not bipolar and don't have borderline persality disorder, it's autism. I am starting to wonder if most of these issues are actually a form of very long term burnout after childhood trauma, being in hospital with diabetes and dealing with school.

Since the age of 16 I've had varying levels of exhaustion, brain fog, inability to deal with everyday life stuff and what I thought were some kind of mental breakdowns and I now think are probably meltdowns.

This has become significantly worse in the last year or so and I don't know what to do about it. I have gone from being highly intelligent, highly functioning and (in my own way) sociable and organised to being an anxious mess, can't cope with everyday tasks like tidying up, putting the dishwasher on, getting ready for bed, deciding what to do at the weekend or what to have for dinner. I have meltdowns several times a week (yesterday it lasted 5 hours) usually over minor things like going to work, changes to routine, changed plans, new tasks, not knowing what to have for dinner... it's like my brain is fighting me and shutting down. I can hold them off for a while but I can't stop them.

Unfortunately my meltdowns have become really bad and terrifying, I have strong suicidal thoughts and a strong urge to hit myself in the head. I even have them at work and I think I'm scaring people. I don't feel able to talk to my GP or counsellor about how bad they are because I'm worried I'll be forced to go to hospital which would be my worst nightmare (I have a phobia of medical stuff) and I don't think it would help, I've had bad reactions to antidepressants in the past. As soon as I've gone through the meltdown my brain feels clear and I feel a sense of calm, as though I have no choice but to go through them.

I am hoping that someone here might be able to help me in the following ways:

• Does anyone have any information about burnout / meltdowns that I can read? I hope that understanding what is happening will help me explain it to my husband.
• Does anyone know how much of this I can tell my GP? At the moment they think I have "mild anxiety" because I am so good at masking but I need them to know that it's not "mild"!
• Any suggestions on how to deal with burnout? I keep being told to take time off sick from work and rest but part of my autism (I think) is that I have to be busy all the time and I can't be on my own. If I don't have a plan for a day off and I don't leave the house before lunchtime I either feel really uncomfortable or it triggers a meltdown - I need to rest but I really can't do it. So, at the moment, I am dragging myself through work and falling apart in the process because the thought of having more than a couple of hours on my own is terrifying. 

For those of you who are worried - I'm safe, I have an agreement that I phone my husband when I feel a meltdown coming and we have plans in place to keep me safe. I just don't want to keep going like this for the rest of my life, something needs to change which means I need to either get help or understand what's happening to me.

Thanks again for reading.