You can't still be pregnant if you weren't pregnant before (the test was negative, as you stated).
Perhaps you have an infection of some sort. In any event, you certainly sound stressed. Why not make an OB-GYN appointment and explain what you wrote here? If it's an emergency, they'll do their best to fit you in earlier or will have you go to the ER. In the meantime, waiting around and fretting are not doing you any favors.