Welcome to the boards!
It sounds like you're feeling a lot of pressure to feel a particular kind of pleasure. That must be tough. I don't think there's anything "wrong" with you; being stressed about what you are and aren't feeling is a really big turn-off, so it's not surprising that you're not experiencing a lot of pleasure from what you're doing. It's easy to think that our body is some kind of machine and if you touch the inputs in the right order then you should feel arousal or sexual pleasure but in reality it doesn't usually work like that. Our biggest sex organ is actually our brain, and it's how we think and feel - the context in which we're touching ourselves - that makes something feel sexy or not. Does that make sense?
So, I suggest that first off, you give yourself a break. It takes practice but if you can change your thoughts from "do I feel turned on?" to "how do I feel?" then you can take off a lot of the pressure on yourself. Start noticing pleasure - not just sexual pleasure, all kinds - in your day to day, notice when you feel good or relaxed and try to enjoy that without it needing to be anything. Over time, you can start to notice if there are times when you feel sexual, or thoughts/fantasies that feel sexual to you and let yourself explore them without pressure or an end-goal in mind. Let the things you do with your body follow how you're thinking/feeling, rather than trying to use your body to change your mind. What do you think? Is any of this something you might try?