You could be asexual. It could be that you're stressed, your hormones are low, you have no-one of interest to spark that in you. Anything.
I don't think everyone is obsessed with sex at all, but there's nothing wrong with not being interested in it. I blamed the pill for my lack of sex drive with my ex, but I have a high sex drive with my current boyfriend so it turns out it was because I didn't find him attractive and the sex was bad.