What Causes Lower Abdominal Pain Along With Vomiting?

Stufflook a pregnancy test a week after 16thhercourse and it came out negative so four days later I took two more and they came out negative but I feel different I m tired everyday my cramps I ve been having cramps in my stomach like crazy and I have white vaginal look mucus Stuff or discharge and I don t know what s wrong with me but my stomach gets adominal pain from like the lower area and sometimes at the top and I ve been getting feeling sick like I ma throw up a lot but I don t & my period is 2 weeks late