First time having sex !

So i’m 16, lost my virginity last Friday n from Friday through Sunday we had sex 8 times, there was no use of contraception which was obviously stupid and he did cum in me🙃, but ive come on my period now so it’s all good i hope ! but ever since Saturdayish I’ve just had the worst pains in my lower stomach and have just been in pure agony. I never get period cramps, and I’ve also had no appetite whatsoever, hardly eaten anything since Friday night. has anyone else had a similar experience with the lack of hunger and the lower stomach pains? X