I had protected sex and had my period 2-3 days after. it was a full 7 day period. its been two weeks, and began having intense nausea, cramps and breast changes. could i still be pregnant? if not, what may it be? am i being paranoid?

Occasionally two follicles mature simultaneously, which produces double the peak of estrogen, and the drop to near zero just prior to ovulation will produce similar symptoms (cramping, nausea, breast tenderness) as at menstruation. The severity of symptoms may also be due to pelvic endometriosis, with abdominal implants, and similar symptoms such as described.

Condoms are very effective at preventing pregnancy when used correctly. It sounds like you had a normal period after sex which would verify that you are not pregnant. Consider doing a home pregnancy test. It will be negative. This may help alleviate your anxiety. Consider coming in for a visit to discuss birth control options. We can help you avoid these kind of scare. Great job using protection!