What Does Stomach Infection After Unprotected Intercourse Indicate?

Hello, i recently was on the recieving end of unprotected anal sex, im unaware of how many partners he has but he told me he was frre of any diseases and infections when i asked. He was also circumsized and he came inside me. I showered, peed and douched all within an hour after we were done. 2 weeks have gone by and i now have some sort of stomach virus. I went to the doctor and said that there have been many cases recently. The doc pricked my finger and found nothing wrong with my blood and said it probably just a virus. Could i still be at risk, please and thank u. Also a note: this was my very first time having any sexual contact with anyone. Also, i was very scared to talk to my doctor about this because my mom was in the same room.