I'm horrible in bed 😔

Today my fiancé came home from work early because he wasn't feeling good. I told him that tonight I would give him head since he's been wanting it lately, well while I was giving him head I started getting really horny and asked him if we could have sex and then he could finish in my mouth. He said alright so we got busy but I could tell he was getting tired so I tried doing some of the work which Ive never really done before so I had absolutely no idea what I was doing but I don't think it was good because he flipped me back over and I started giving him head again so he could finish but it just made him soft.. and it happens literally every time I try and do some of the work. Usually I don't want to because I can't move my body like a lot of other girls can, especially my hips, I've got no sense of rhythm or anything (which sucks even more cuz he's a drummer so you know he has really good rhythm) and I know it's not cuz of the head cuz I'm fairly good at that I just can't be on top or do any of the work and it makes me cry every time he can't finish because I know that a lot of other girls are good on top and he deserves to be with them because at least they can please him... Is there anything I can do to make me good at being on top? I try to do it all the time cuz he says i just gotta practice but practice isn't doing shit.