Ok, So February 11th I had my period, then on February 16th I went to visit my boyfriend and on the 16th and 17th we had sex (I am on birth control) then in the beginning of March (last month) I started having headaches, nausea, back pain, frequent peeing, constipation, sleeping all the time, tender breasts, and I missed my period I took 2 pregnancy tests and both were negative. Then last week I got my period, but I still have all these symptoms. Is it possible for me to be pregnant? I am only 18 and I want kids, but not yet. I am just worried cause that is the first time I have ever missed my period. Please help if you can.