What to do about birth control?

Naomi
I have been with my boyfriend for over a year and we have yet to have penetrative sex. This is solely due to the fact that I am not on birth control, and I am not comfortable only using condoms. Since the beginning of our relationship we have been very physical as well as have had good communication regarding our sexual interests/limits. 
Early on I made a point to tell my mom that I am not "sexually active" (we aren't having "SEX sex"). (He's my first real boyfriend she always knew I am a virgin, we're super close with eachothr, etc.) I just felt like I wanted her to know. 
I also know that she wouldn't care if I were to start having sex, but at the same time, I don't want her to wonder if every time we are in my bedroom if that is what we are doing. This is why hesitate to put myself on birth control. Because even though I'm 18, I am still on their insurance. So I'm not even sure that I want to try to hassle with this issue. 
I could always vaguely inform my mom that my doctor wanted me to try it for cycle adjustment. But that comes with its own issues. I don't even know if I WANT to go on birth control because I don't want it to make me gain weight or make my anxiety worsen. 
ARGH. Any words of advice?