I would say it could totally be the birth control! I'm 24 and I was on it for a couple years. It seemed like as soon as I was on it, my want for sexual contact was gone... and even if I did want to be sexual, it was like my body didn't respond. Idk it's weird. When I went off it, I got my sexuality back. Sucks that I can't have sex now. I'm paranoid of getting pregnant, so luckily there are other things lol... but anyway, yeah. Antidepressants make it difficult too, but I've adjusted to that. Oh, and I definitely agree that being tired is counter to sexuality.