Everyone makes mistakes, fucking hell I've made a fair few I wouldn't relish bringing up ever again.
Is this mistake ever likely to rear its ugly head again? I mean like does it depend on one person keeping their trap shut, or are you the only person who knows?
The other thing to keep in mind (and I'm guessing because I'm blindly stumbling about in the dark not knowing what it is, (and that's not an encouragement to say, you shouldn't if it'd make you feel worse)) is that it's possible you don't have the best perspective of it given you're smack bang in the middle of the situation as well as being on AD's (and I'm not suggesting you're incapable of rational thought because of that).
It would be unreasonable for the people around you not to respond with support when they see you're distressed. This could be either because they're not listening and taking you seriously when you say how you feel, or you could be playing down the seriousness of your feelings to those around you, which even in this short thread are pretty alarming if you're desperately scrabbling about to find reasons to keep your life.
Are you able to say what you've said in this thread to the people you know in RL?
From the outside I would say you need to look around and decide who would be best placed to help you feel the contentment you're looking for (and just guessing again, but I would say that would be your GP), and decide what words would get across to them how much this is taking over your life.
If everyday is getting harder then now's the time to do something, everyone is unhappy with their life to some degree, but you posting this makes me think you know this isn't the everyday pissedoffness people normally have to put up with.