Theres no way i could be pregnant, right?

ok so I'm on nuvaring, i had on may 18th and took the ring out for an hour or so, but he didnt *** in me. i accidentally left my nuvaring in for 31 days instead of the usualy 28 and i had again on may 21st and he did *** in me, but i took plan b the next morning. I'm thinking theres no possible way i could be pregnant, but usually even if i try to skip my period on nuvaring, i get it anyways and i havent, so i took it out friday to see if it would start and it still hasnt. Ive also had headaches and been a little nauseous. I took a test on sat. but it was negative, should i wait and take another one??