I'm not going to hook up with my girl whenever she wants to.
Why don't you want to hook up with her?
She pressures me too much and I just want to sleep.
Good for you for standing your ground. You should not feel pressured by your girlfriend to have sex at all.
She pressures me to do it even if I don't want to, because of that I don't want to have sex with her at all.
Well I think you should just stop talking to this girl if she is making you uncomfortable. Because no one should be pressured into sex.