Girlfriends friend making moves

I must start of by saying that this is my first post, and english is not my first language. This might be the wrong forum to post on.

Anyway, I was out at a bar with my friend (male) and my girlfriend and her friend. Everything started out fine but after a couple of drinks i noticed how my girlfirends friend started to get closer and closer. She had her hand on my thigh and almost rubbed my (you know what area) whit her hand. When my girlfriend went to the bathroom her friend also kissed my neck and cheek, and she also activly tried to hold my hand under the table etc, and constantly tried to lift her leg ontop of my leg under the table.

Is this just normal flirting and im overreacting or what should I do?