You were a week late with three negative pregnancy tests but had pregnancy symptoms and when your period came it was light with no clots but was on and off?
I suggest that you get a blood test done for pregnancy. Some womens bodies just don't show it in a regular urine test. Or, if this is your first maybe your body is trying to get ready for pregnancy. Either way you should consult with an OBGYN who can answer your questions and concerns.