Help!

Hello, I have a very big question, I was with my partner on Sunday and I did not think I was going to have the sexual act that I am "virgin" the thing is that his penetration once and it was the lack of protection, my great fear is that My ovulation period was from February 16 to 22, and this happened on the 25th, my fertile day was considered to be 21 and I do not know if I had only been pregnant and that I had gotten it once and how I had seen it. preseminal carries sperm ... and since that day 25 I have pains in my belly as if the period would come ... Help: c