How do I know if I'm in a codependent relationship?

I don't have too many friends, and I've been in a relationship for 8 months with an awesome woman. She has a daughter. I've fallen in love with both of them. Well, she just left for Hawaii today because all her family lives there. I couldn't afford to go with her. Since she has been gone, I've had erflies in my stomach. I feel sick and I miss her and her daughter already. We have been inseparable for the past 8 months. We do almost everything together. I don't really have friends because when I was in my early 20's (I'm 26 now), I got in with the wrong crowd. They started doing drugs and I went my separate way to avoid getting caught up in that kind of life. I find it hard to make new friends at this point in my life. I work full time and go to school part time, so it's hard to find a hobby. I will admit, I'm whipped. I do everything for my girlfriend, but I keep thinking that she is going to get sick and tired of me and leave me. Advice?