(18\m) feeling insecure, need advice on how to cope.

I've been away from my GF (16\f) for a good month or 2 rather because the few times I've seen her since I graduated was a quick hello and goodbye at her soccer practice. I can't take her out to dinner or a movie or to my house without acceptance from the family. I've gotten the ok from her mom, the parent she lives with, at a formal dinner with my family. I just have to meet her brother at her home. So for the past 2 months she's seemed really distant. This bothers me because she's really close to at least 2 other guys, and, well, I'm jealous. And also very paranoid. I try not to let this show to her but it's hard. It really hurts me too because I'm very insecure about myself. Before school ended she was very lovey dovey with me which is what I needed to feel confident in myself and I was sure that she wouldn't be doing things behind my back. But lately she's barely held conversations with me and will dissapear for hours with respond with a simple I'm sorry I was sleeping/busy(usually will say baby sitting/cleaning). She doesn't call me and doesn't skype me anymore. She also used to be very, ahem, Sexual. With me. An erotic conversation would occur frequently with her starting it off. Now though, nada, I try to spark softly saying "I wish we could be together (wink face)" and she'll reply "Lol :)". We've been dating for 7 months now. I do feel happy with her. I love her and I hope this is just temporary.

What I'm asking for is reassurance or tips to reignite the relationship. Thank you in advance.