Had sex without a condom for the first time

This past weekend, my fiance and I had sex without a condom for the first time. He pulled out before he came but now I am nervous that I could have gotten something inside.

I just ending my period on February 27th and we had sex on March 1st. He put a condom on before he came also to finish having sex.

What are the chances I could have gotten pregnant? I won’t get my period again until around March 18th.