I went through this earlier this year. Just all of a sudden DH and I noticed a lot of weird things: low/no sex drive, irritability, hair falling out, mood swings, etc. We hadn't moved recently, I hasdn't switched BC, or any other life-changing things. I went to the doctor to get my hormones tested and she said I had the hormone levels "of an eighty seven year old lady."
Talk to your doctor about it and get your hormones checked out. Mine put me on an all-natural suppliment called Deproloft, and told me to change my diet. So far, so good. BUT low hormones can have a big role in you having kids or not. Low hormones = harder it is to carry a baby full-term.
Get it checked out pronto. GL!