Hi everybody, thanks for all your comments. Not sure if anybody is even reading this anymore. But I talked to my mom tonight and said this.
First off I want you to be a little easier on me. I'm in a new relationship and I'm still figuring things out. I'm trying to be around you more and not seclude ourselves from you (she feels like we do that, I didn't realize thata what I was doing though but I guess thats how she sees it) But I also want you to know that GF makes me very happy, and I need you to be happy that I'm happy. I need you to trust my decisions and let me make them on my own. You have to let me go a bit because I'm 22. Also whatever approach your using isn't working. The subtle silent treatments and possibly subconsciously being cold to GF won't work out. Because she notices, and she feels bad. Maybe instead if you want me and us to be around more you could ask us to play cards, or go for a walk.
Anyway she said that it's very mature of me to say this, but she thinks GF is figuring out where she stands in the family and is being slightly possessive of me. But she(mom) will try and back off.
Not sure if she was to happy about what I said because she just went to her room and shut the door.