Fear of anal sex

Hi guys. I hooked up with a guy at a nude beach. As I remembered, we didn't have anal sex but we were hold each other's penis and he also put a finger in my anus. Even though I can't remember any details about having anal sex with him but I'm still feeling scared if I may have got STDIs through anal sex with him. I also imagined having anal sex with him and thought it possibly happened. Can anyone help me overcome this fear? Thanks.