Re-read your post and notice how you are hostile towards even the idea that others can attempt to help you (which has the unfortunate side effect of preventing you getting help). You think they don't understand and can't understand why you feel so low. At times you can't even explain it to yourself, you just know you wake up some days even struggling to find the will to do anything. On your worst days you can find yourself standing back at a railway station which you then realise is to give yourself long enough to talk yourself out of jumping to end it all. Even on your best days, you can sometimes find yourself wanting to make others laugh to try to cover up how your really feel and even use it to deny to even yourself you are so low and then you feel like you are being crushed by how low you feel inside.
You think I can't understand, you're wrong, I'm describing myself. I've lost count of the number of times I've thought about killing myself. Looking back I've now struggled with depression for over 35 years. The difference between us is less than you realise. Perhaps the only real difference that matters is that I've started to notice (and you need to notice) how we can deny it to even ourselves which has stopped us seeking enough help.
You're strong enough without ever realising it to not even really be afriad of even your own death, so is asking for help really beyond you? ... Its not, you just at the moment denying it to yourself.
The fact is the best psychologists have heard it all so many times before, nothing you say to them can really shock them any more and they can help you. At the very least they can give you an independent viewpoint to help you see and compare your thoughts with and so help you find a better way forward. And anyway, knowledge is power. The more you learn the more it can help you in all sorts of ways. You just have to take the next step to ask for help. The one's who deny its needed, (and will tell others that) are really trying to convince and deny it to themselves that its needed. Its all part of the denial. So many ways to deny it, but once you cut through the denial and realise you already have the strength to find help, it really can help you.
Plus as you say, as you are someone on the autism spectrum, (that's something else we have in common) that means you've got the capacity and interest to study subjects in great detail. That's a strength, not a weakness. Also being different from most (not all) but most other people isn't wrong, even though you're heard it is wrong, so many times you can't even count it how many times you've been put down for standing out from the crowd. We are pack animals, we want to fit in and the one's who want to be the pack leaders, don't like it when we don't follow what they want the pack to do. They also don't like it when we speak about our interests, because then they are not the centre of attention. Like I say, knowledge really is power because the more you learn about psychology the more you'll see all sorts of behaviours from others, some of which from others that have caused you great harm in your life. (For example, the one's who want attention, want to be different, so they can stand out and don't like you naturally standing out from the pack. The irony is they want what you've always had. Remember that the next time some tries to put you down for standing out through no fault of your own). This is just a small glimpse of what psychology can show you and many will try to deny it, because they fear, hide or simply deny it for so many reasons. Learn to see the reasons and its amazing what it'll show you over time. You can get help and it will really help you.