Inclusion of a non-contributor co-author
I'm sorry to hear all of this (and also sorry about the downvotes without hints how to improve the question (but sometimes they seem to be just a way to greet new users in this site)).

It was right to question the authorship. On this site you can find many good answers on this topic.

I have two hints for you: first, as Mr. Eldredge says in the comments, please see a therapist. Your problems are far too serious, you need someone to talk to.
Moreover, please look that academia is not your complete life. Do other things in your spare time that fulfill you. Don't work too hard. Spend time with hobbies and friends. Then problems at work/university will be not so important as they seem.

Good luck! I give you morally 1000 upvotes and wish for your best!

Edit: I don't know whether it is allowed to say here, but there is also "AskAcademia" on Reddit. My opinion: The topic is similar to this site, but the people there are much more "human" than here and in general, friendlier. (The quality of answers is not always so high as here, though.)