Any Ideas?

On the 18th (Friday) I finally took out my nexplanon implant and before I took it out I was on my period for 4 months and then after my period stopped. Last Friday I had sex w/o condom and my boyfriend came inside me and I took a plan B and for some reason I felt weird and I mean weirder than how my body usually reacts with it but i just ignored it. Tuesday and Wednesday of this week had sex unprotected and didnt take plan B so then I started getting cramps yesterday and then I started spotting and then my period started but its lighter than what I usually expect it to be. Yesterday I also took a pregnancy test 3 times the first two times it was unreadable because I guess I used wrong and my boyfriend and I were just there reading how to use it properly and the 3rd time it came out negative but I feel weird. Vomiting and cramps and then my light period. I don't know, am I pregnant? What should I do?