OK so I'm really confused.. I remember having a period mid week of Jan. I didn't have a period for the month of Feb. I'm normally regular and have a 28-30 day cycle. I have unprotected sex for the months of Jan and Feb. today March 17 I noticed there was light tan brown on the tissue I used. I've taken 3 pregnant. Test all negative. Could the light spotting be my period? Or implantation bleeding?

If you've had unprotected sex and missed at least one period (february, right?) I would lean more towards implantation bleeding. Go to the dr's

Pregnancy tests aren't nearly accurate until at least 2 weeks after implantation. Some people do miss a period, due to stress change of diet or exercise patterns etc

Go to the Doctors, they'll tell you for sure, and you won't need to stress anymore. Tell the doctor 3 tests were negative but you're still not sure. The doctor will be able to give you a near certain answer with a more accurate test.

Hope this helps,
Louis.