Hey Tempy,
Good to read your new posts.
I do believe staying in contact with the Samaritans is a good thing, keep on writing emails with them (or phone). They will never judge you, they will understand you too and might come up with something you haven't thought of and is really useful.
I do understand your life is pretty tough at the moment, life can be like that and that you get upset or depressed is very ubderstandable. You do have a lot to deal with at the moment. You can't change everything all at once, you can't solve all your problems at once, but you can take one step at a time. If you cannot deal with some issue at the moment, then leave it till you can deal with it. Just deal with one thing at a time. You don't have to tell your mum that you are gay now, do you? Tell it when you can deal with your mums reaction. It doesn't hurt to wait a bit longer to tell her?!
With not getting an aspie test is like you are not being recognised by your doctor, not being believed. Try to find a way that you get tested, ask for a second opinion, pay for it yourself, but only get tested if you want to and think it would benefit and help you (health wise). You don't have to convince yourself and us and hopefully you girlfriend too of who you are.
Your relationship seems to be quite stressful at the moment too. I don't know what to say. You can tell your girlfriend that you understand why she gets agitated and that it is not what you want. All this stress and tension of doing the wrong thing can make you become worse, just because you want to do it right... I don't know if this is true for your, but my experience it was like this, getting stressed trying to do it all right and than just ending up making things worse. It doesn't hurt to tell her that you are trying your best and that you want to do things right, but because of stress and anxiety you are making more mistakes. You can ask her what she needs to become less agitated and stressed. It looks like a vicious circle that needs to be broken and that is not easy, but it might be possible (with some help).