plan b symptoms or pregnant???

So I had unprotected sex on Dec 1; he didn't ejaculate in me or was close. I took plan b as a precaution 2 hours after. I got my period a week early, which was also a week after I took plan b. After I had my period I began to experience cramping in my lower abdomen and vagina. This started two weeks ago. I have also been experiencing nausea and dizziness every so often like 2 days last week, and it started up again now. I still am experiencing the cramps mainly in my vagina but it comes and goes but between long periods of time. I have also been a ting very hormonal and mood swings (but I can't tell if that's because I'm back home from college and my family stresses me out) & my boobs have been sore (again this feeling comes and goes between long periods of time)
I'm NOT on birth control