I don’t know what’s wrong with me

So about 3 weeks ago I had unprotected sex, I took the pill. But now I’m having really bad headaches like 5 times a day maybe more, and I keep having like cramps and every once in a while I feel nauseous and get a little dizzy and I’m more tired then normal. I did get my period but I only had it for like 4 days, the one day was very heavy and then the rest of the days weren’t. Like I don’t know if it’s cause I’m on my phone to much cause in a way I am but I’m not, but I don’t know what is going on