First thing to do, take a deep breath, just relax, concentrate on your breathing, don't let these thoughts affect you for a bit, just breathe. In and out, do that for a couple minutes, just to calm you down if your feeling bad, can help for a short term.
First of all, you need to approach this situation with your female friend, you have to sit there and tell her that you are not interested in her boyfriend and that you do not hate her. Show her that, hug her even just show her that you don't hate her, you're ok and you aren't interested in her boyfriend. I would definitely not use aggressive tones though, like, don't call her boyfriend an ugly child haha. So it's just calm, nice and smooth, be relaxed and confront her in a nice, healthy manner and show her how much she cares to you and how you would never do such a thing to betray her.
For the severe depression, if it is depression, then it's best to see a professional about it. Sometimes these dispositions may not be environmental, but chemical and sometimes it's very hard to control. There are many methods that a psychiatrist might be able to recommend to help ease your depression, including medication, but all in all it can be for the best. So, I think (if you haven't already), see a professional about the depression. Whether it's a therapist, psychologist or psychiatrist, whatever you really prefer.
There are also some organizations that can help you find jobs, you may also be applicable for well-fare or equillevant. The main thing you have to focus on is the positives, think of the negatives as something to try and fix for sure, but just stay happy, calm down and know that the future is uncertain and if you play your cards right, it can be good.
Nevertheless, if you want to chat I'm always here
. I can be found on Steam mostly:
http://steamcommunity.com/id/bleese and I prefer to use that medium.
If you don't have/use steam then my skype name is bleesev2
I hope everything gets better soon!