Could I be pregnant? I kept sex 4 weeks ago and had menstruation for 3 . I am suffering a very severe back pain , nausea, headache and sore breasts . I took a pregnancy test and the result was negative .

If you think you may be pregnant , you may have been test done soon. You can take a pregnancy test , provided it is done in 5-6 weeks after the last normal menstrual period , or you can go to your doctor so that you do this test . A home pregnancy test has a reliability of 97 % if a week ago after they missed menstruation, and proof of doctor can safely assure pregnant or not the same day that lacks menstruation . Although the symptoms you listed could be related to pregnancy , could also be related to other diseases as well , such as a viral infection. If your pregnancy test was negative and you still feel unwell , you should call your doctor. Good Luck!