No period for almost two months help??

So after having spotting for 3 or 4 days i just realized i havent had a period since May 18th but still negative tests. Anyone had negative test but found out they were prego? I have an appointment wednesday i dont expect a positive result but i figured id ask and see if anyone has had this before? Havent changed anything in my day to day no huge stress and haven't been on birth control my periods have been normal for 7 months straight with no wavering. Trying to stay positive so i dont freak myself out. Any advice?