Idk if i should test

3 weeks ago i had unprotected sex and was off my pill for about 2 days but the week before that i wasn’t taking it 100% perfectly i kept forgetting days and taking it super late, well the guy did not pull out and we did this twice, but i got my period the next day and it was only for a few days it stopped completely out of nowhere, i was still cramping and having back pains and the blood didn’t lighten up, it was still kinda heavy so idk why it randomly stopped, but as of this week i am always nauseous but not enough to throw up i just gag sometimes like when brushing my teeth and i’m really bloated and my nipples are kind sore/tingly and yesterday i was getting some small cramps and back pains but then it went away i was gonna buy a test today but idk if i should