rghltifndn Very pleased to see your update. Well done!
I've been very ill and am actually posting through a haze of drugs if my posts seem odd, and I'm struggling to edit, but I deeply relate to you coming to the end of the line because different circumstances have brought me to mine and my own AIBU and I am so very glad I overcame my sense of shame to post.
I so wanted to pick up on what you said about a lack of support or existence of ... "family or friends probably because I am a horrible person with mental health issues. Apart from you sounding anything but horrible, 
It's actually also the very least likely reason.
The position you are in, in the situation you are in, and the selfishness and self preservation of that from others, is why, and sadly it's common.
I'm in a wheelchair, two of mine have disabilities, and I'm a low income, self employed, lone parent who doesn't tick the standard 'entitled to' boxes.
Without going further than that, do you think the reason I lack friends family and support is because I'm horrible or because it's just so much easier for others not to bother?
Or/and, that those I do have tend to be flaky because the ones who can see past all the reasons not to know me, have huge problems of their own?
That my values might be so hugely different to what little family I had that it's a non starter?
In my darker moments it's easier to turn the unfairness of the world onto myself and blame myself, my personality, how well I do and don't manage, and every choice I ever made etc, but it's just ignoring the elephants in the room.
A huge amount of my problems could be solved if I had the money for respite, assistance, a PA, transport and a social life! It wouldn't take away my Dc's needs, or mine but it would make it possible to manage them and actually have a life and a more balanced social network!
Once you your whole life balance and situation are better sorted out you'll see all of this for what it is, and it isn't you!
The situation will get better, but it will take time and the less money's available can affect how long things take and that's why I'd advise you to keep this thread going and updated, even if it feels odd, because you'll find the advice, knowledge and information that others offer as well as emotional support may turn out to be gold dust. ie: funds from charitable organizations specifically for teachers has popped up above, along with referral for CBT or therapy through work and how normal it is, rather than the (understandable) fear of damaging your career if they knew.
The summer scheme project I'm engaged on (now remotely from hospital!) provides free creative workshop places for children (inc ASD) based on self declared financial need not markers like FSM, benefits etc. It's part of my contract they have to oblige to get me cheap!
They don't advertise it as they're afraid of being swamped by CF's pushing out the genuine, so parents like yourself tend to find out through diverse routes.
There are other projects doing louder trips out, sport etc, but ours is differently focused with differentiation to ensure physical and neurological difficulties don't lower the quality of the offer, and routes to try to find ways to cover expenses that might stop a parent being able to send a child.
It would be coincidence if you were local to it but you never know, or another doing the same. It might only be suitable for one child but in turn let you tap into something connected for under fives, ect. ( I'm also involved in providing free adult creative workshops as part of social prescribing by the way, but people don't need a referral)
All these bits and pieces are out there and the MN knowledge base is widespread as well as all the emotional support.
It sounds odd when i read my own thread back but even though I knew I was on my last legs physically because I wasn't getting help from where it should have been coming from, it actually took a bunch of strangers on here telling me I sounded 'really poorly' and pointing out what should be happening and all the things that they get, for me to start asking the right questions!
I'd never describe myself as 'really poorly' and have been surprised to see how medical staff react to those two words!
So when folk here ask you how you are, tell them, this stuff isn't shameful even if we've been made to think it is.
You've done the right thing, and so very glad to read that you've got the ball started rolling, but you must be so exhausted and fragile right now, so please do what is right for you in terms of privacy and where you put your energy, but I think you should view this thread as part of your support network.