Am I Pregnant ? (Under Aged )

I just turned 15 years old, before my birthday I had sex WITHOUT a condom MULTIPLE TIMES. (I know very stupid and careless, i regret it.) About a month or 2 ago, both my parter and I thought He came inside me so we asked my mom to buy the plan b pill. We understood that its not guaranteed to work so we were still worried. I also took a pregnancy test & it came out negative. I know the emergency contraception throws your period off for about 2-3 weeks , so finally about 3 or 4 weeks ago I got my period BUT I dont know if it was my actual period or IMPLANTATION BLEEDING. So both me and my partner were still scared. Now today, my ENTIRE stomach is killing me, it doesnt feel like normal like regular period cramps its WAY WORSE 'Glow' says my periods suppose to start tomorrow but remember the pill messed up my period so I dont know if tomorrow is the actual day. Please help I'm terrified.