there are a few things you can do... from my experience.
embrace the jealousy and realize that it is usually a sign that you are not getting your needs met in some way. If you can figure out what that is, then you can tell her. Perhaps talking to her will get you to a place where you can figure it out. go through every idea you might have about what you think is at the route of your jealousy and see if you find something that is a need. If and when you find it then you and her can work towards it. It could just be that that will make everything fine for you.
Besides that, perhaps it's all just a bit fast. It seems to work better when people know each other and have a chance to communicate together, spend time seeing each other for who you are and what is going on for you both. Chances are he has stuff going on too.
Other than that, things take time and a whole lot of adjusting. Anyone new coming into someones life is an adjustment. This is no different but far more intense. Pace yourself and ask her to go at your pace so that you can catch up with yourself and her and begin moving forward at a pace that is suitable for both of you together.
Anyone want to be friends on Facebook?
Send me your name via PM