I can't recall my sexual encounters with my fwb

Is this normal? I sleep with a friend on a semi regular basis. He's visited me out of state, I enjoy his company. I think it's mutual. I'm very inexperienced in comparison, hadn't had sex til my mid 20s. But I realized I was trying to think of a specific moment that stands out... and there is none. I feel broken and embarrassed that I can't remember any of our rendezvous. Maybe because it's repetitive or because I have a brain injury... should this concern me? Is there something I can do to make it unforgettable? I get so socially awkward and anxious and it's very routine: go out for dinner, go back to a hotel room, putz around, no urgency or flirting. Maybe that's the problem.