She doesn’t like you. It could be a matter of no attraction. You guys could be physically stuck on each other, but maybe she doesn’t like the real you. If this is the case, don’t waste your time trying to change yourself. Find someone more suited to deal with who you are. Because once that physical attraction fades, there’s nothing left.
Nothing in common. You don’t need to have everything in common with her, but you do need something that connects the two of you. If you guys can’t come together on anything, anything, then you need to part ways with her. It’s a wonder you hooked up with her in the first place. Could you imagine a first date involving two people with nothing in common? Watching paint dry would be more enjoyable.