pregnant or stomach bug??? :update:

so on october 17th i had my unprotected sex but he didn't cum in me it was also the last day of my period. After that i felt really sick i'm not sure if i ate something that made me sick but everytime i eat i just feel extremely nauseous and just horrible. Now i feel the lower abdomen cramps all day and i feel nauseous with headaches. idk if i could be pregnant or it could be the same stomach bug