Not sure if it'll help your situation but I noticed a drop in libido. When I looked into it I had slightly elevated level of cortisol which is related to stress response in the body. My doctor had me try and take one 500mg pill of L-Lysine supplement once a day with a meal. I never felt like I had anxiety or was stressed out, nor did I feel like I had issues with seritonin levels. After about a week of taking this I noticed my libido was coming back and I felt a lot more at ease. Come to find out I was so used to having slightly elevated levels of stress and anxiety I didn't really notice it. Now I feel great everyday and my wife is loving every minute of my greatly effected ( in a good way) libido. Like I said, I don't know if this would help you or not but it did wonders for me.
Life passes up fast, remember the past but embrace the present like there's no tomorrow.