You should seriously consider seeing your Physician for advice. It is recommended by ACOG guidelines, women be screened for cervical cancer by the age 21 or three years within first sexual intercourse, whichever comes first.
This should be done since your problem seem unrelated to stress, change in diet. There is the possibility, your problem is due to the fluctuation in hormone levels that occur every time you and your boyfriend fool around (with your clothes on), however.
This is simular to women who uses birthcontrol pills. The pill increases the levels of hormones and when the levels are high, they have no period until the get to the inactive pills in their package.
Nevertheless, concider this and talk to your doctor: Each time you and your boyfriend fool around, your body produces higher levels of hormones. Higher levels of hormones are thought to increase breast cancer risk.
Hope this answers your question!
REFERENCE(S)
1. Tim De Santis, M.D., Cervical Cancer Awareness (Online: Institute of Women’s Health, 2006) http://womenshealth.med.miami.edu/health_topics/cervicalcanceraware.asp
2. (ASC) American Cancer Society, Inc., Alcohol Increases Hormone Levels, Raising Breast Cancer Risk (Online: ASC, 2001) http://www.cancer.org/docroot/nws/content/update/nws_1_1xu_alcohol_increases_hormone_levels__raising_breast_cancer_risk.asp
3. Gad B. Kletter, Hormones: A Human Hormones (Online: The Hormone Shop, LLC., 2006) http://www.thehormoneshop.com/hormones.htm
The Prison Hospital
Prisoner: Look here, doctor! You've already removed my spleen, tonsils, adenoids, and one of my kidneys. I only came to see if you could get me out of this place!
Doctor: I am, bit by bit.
-- Aha! Jokes