Am i pregnant, or is something wrong w/me?

Ok so I am ten days late! My periods have been regular and on time since I had my first child 8 months ago. All my cycles are 39 days apart. I have NOT been stressing, I am NOT taking any meds... I have been cramping for the past ten days and sometimes they kick in up a notch. I have been having alot of gas too ( sry I know tmi ) and yesterday was the first time I felt really nauseas out of nowhere. I took a test this morning being 10 days late and it came out negative?? And remember this is my first time being late. Could I have taken it too soon? Could there still be a chance that I am pregnant? Or could it be something else? I haven't gone to the doc because I do not have insurance =/ I would really appreciate the advice!! =D