I'm so glad to see that you have finally gone to the doctor. Blood tests aren't too bad once you have had them done a few times. But if it turns out you are pregnant, this will be a fear that you need to conquer. Pregnancy entails a lot of blood samples and a whole mess of uncomfortable things done to you.
Good luck.
If you're not pregnant, my advice would be to possibly ask for a different form of birth control.
There's the depo shot, the nuva ring, all kinds of possibilities.