I don't have a regular period at all so I have no idea if I could be late or not but something doesn't feel right... Me and my boyfriend had sex almost 3 weeks ago and since then I've been having cramps, I've been eating a WHOLE LOT more then I usually do, I'm moody, I feel exhausted all the time, headaches, I feel sick off and on, hot flashes, and my breasts are only a little sore. I took a pregnancy test but it came out negative... but I'm still having all of those problems... please help