Oh man I know the feeling so well. I used to be happy when my period came so I would not feel so guilty. Not only did I not want sex, I started to put on weight, and not just a little, a lot of weight. Talk about feeling like a "Debbie Downer".
I had a medication change and that is no longer a problem. Research on line and see what you come up with. That is how I found my new bipolar medication.

Hang in there. There is lots of help out there, just need to find the right nitch for you.