I am a 20 year old female who has a 14 month old daughter, and i've had an ectopic pregnancy june of last year and miscarriage dec. of last year. My periods have been regular for the last 2 months except for this month. I have this crampy feeling like it's going to come but it doesnt, i did take a home pregnancy test 2 days ago and it came back negative..now i'm feeling constipated, im sleeping a lot, my boobs hurt, and i'm having nauseous spells..what could this be