Need help please

I am ttc and I have been experiencing weird symptoms. I had my period feb 5-11 (it was lighter than usual) had sex feb 22 and spotted very lightly on February 28. Today I have been feeling cramps, bloated, shooting pains in nipples, and light headed. I have no medical problems and took a test tonight but it was neg. what do you guys think? Could I be pregnant or just tired?