I don't know what I should do. I've faked my emotions for so long that I don't even know when they're real
That's no good. How much does this happen to you?
Several times a week. Even with my girlfriend, I sometimes can't tell if I'm in love with her or not.
A relationship is built on trust and honesty, so you should communicate to your partner how you feel. Better to be on equal footing so you both can make the right choice for your relationship.
I'm scared she won't love me anymore.
If the relationship is going to last you need to make sure you both really want to be in it. Be honest with her and you guys can work through these feelings together to make a decision that's right for both of you.