Can I get pregnant? Help!

My boyfriend and I had sex yesterday without protection. The first time I’m not sure if he came inside, but he didn’t do it outside either. After in the afternoon we had sex again, but this time he came outside. Today I start my ovulation window. Can I get pregnant??? How do I know if he came inside?? BTW, all those days I was very slippery when we had sex!! Thanks a lot!