unprotected sex? Chances of pregnancy?

Cindy

What are the actual chances of pregnancy if I used the withdrawal method? Or what about the chances of precum getting me pregnant? My boyfriend and I had sex twice today within the same hour. The first time he wore a condom and then ejaculated, the second time was without a condom and he pulled out and then came on my stomach. I heard precum can have left over sperm from the last ejaculation. I'm scared the second time we had sex today his precum had left over sperm and can potentially get me pregnant. Can someone please be realistic and tell me my chances of pregnancy?