Having trouble get'n off :<

Last night my SO said they'd let me "go first" (as in orgasm). I was really happy how intimate they were feeling so I was excited. So we are doing our usual routine... But I was having trouble down there! I wasn't feeling it. I don't know why but I just wasn't able to feel good. It was as if my usual methods were going stale! My SO felt a little sad for me that I was having trouble but they were very happy I was communicating very openly about it rather than just faking it or just going nowhere. So instead I just gave them "their turn" hoping that would get me off. Unfortunately it didn't. I don't know why but I just felt gross and uncomfortable, which is very unusual. We ended up just cuddling on the couch. I felt really embarrassed.