What should i expect when i have taken 3 plan b pills in 4 months when it comes to my period cycle?

That it is totally: Messed up right now. Instead of taking emergency contraception you need to get on a regular contraceptive program. You obviously are sexually active. There are many options including birth control pills, IUDs, depo provera, (medroxyprogesterone) and implantable contraceptives. Please see your doctor.

Agree w Dr. Juchau: You are only 17 years old and have needed to use plan B in 3 times in such a short period of time! You may not be responsible enough to be engaging in sexual activity. If you plan to continue to be sexually active, do recommend a consistent form of birth control. Your period may be normal or may show changes. Possible SE's: menstrual flow changes (spotting, bleeding, early or late period),