My girlfriend had sex with me whilst I was sleeping

This morning I woke up to my girlfriend riding me. I told her to stop because it just kinda grossed me out that she did that whilst I was asleep but she just kept going until we both finished and like I was still half asleep and couldn't really push her off. Obviously I love having sex with my gorgeous girl but i'd just prefer to be awake it makes me a bit uncomfortable that she did it without me knowing. I told her all this and she told me that she was just trying to do something nice for me and told me I should be more appreciative. I don't know why she couldn't just do it once I was awake but whatever. It just freaks me out a bit that she could've done anything like obviously she didn't because she's not a weirdo but she could've done and I wouldn't have known and that just makes me feel so gross i'm trying not to think about it but this whole thing just makes me uncomfortable. I'd been drinking and passed out which is why I didn't wake up but I think she'd been doing it for a bit before I wake up and that just like grossed me out so much. My girlfriend keeps telling me that I was enjoying it because I was moaning and that I ruined it by complaining afterwards but I was asleep man it's just idk it's weird. Am I overreacting? Should I be more appreciative?