What's wrong with me??! (detailed - help!)?

Im an 18 year old female and am in a monogamous relationship. We have frequent unprotected . Lately, I have been experiencing "munchies" - eating a lot. Normally I eat half of everything and not too often. I have also been tired all the time! Except at night when it's time to actually go to bed I just can't get comfortable and end up staying up all night! I've also been constipated but have had some help from a lax. I think it's been about a month since my last cycle. What could this all be? Depression, pregnancy, side effects from HSV-1/2, or something else??!! Help!!