why doesn't my girlfriend treat me well?

I am a lesbian. My girlfriend and I have been together for a year and a half now and I just don't like the way she treats me sometimes.
I love her very very much so I don't know what to do.
She has a very short temper and gets mad about the dumbest things.
She has very little energy and is always complaininng.
She picks me apart for my flaws all the time. (you're too shy. You're too white, you're not like normal people... etc.)
I tell her how much these things hurt me but she dosn't stop she just makes me feel like I am in the wrong for being hurt. She yells at me shen she's mad and pushes me. She's always playing this stupid video game.
Ah! on the other hand she has many good qualities.. and she can be very sweet shen she wants to. I love her, I just feel like I take too much shit from her.
I wonder if I subconsiously put myself into situations where I know i'll get hurt or if it just naturally happens to me.
I don't know what to do. Advice?