Advice please

I broke up 1 year ago with my ex, and I hadn’t had sex with nobody until the 20th of July, I didn’t know well the guy, all my friends told me to do it, and so we did it, we used condom but I’m very worried cause I was on my fertile window, and I don’t talk with him anymore, should I be worried or something? I was very horny and I wanted to have sex with somebody but I didn’t want to have sex with a friend or something and since I am doing a language course in other country I thought it was my opportunity. Do you guys think it was a bad idea to have sex like that?