2 weeks late. Back pain, period like cramps and flu...pregnant?

Hi. Im two weeks late on my period. Having really bad period like cramps. There bareable but hurt. The past 3 days i have had flu or cold like symtoms (stuffy runny nose,cough). I have been having back pain too. Took test 3 days before my period was suppose to come. 5 days late and 10 days late and all were very faint negatives. I have a doctors appoinment for April 13th. My last period was february 21st. I wanted to know everybodys opinions on here. Could i be pregnant with false negatives on 3 test? Why would my period be 2 weeks late? Havent taking any new meds or done anything new. Ppl say it could be stress but i have been stressed way more before and never missed a period. Has this ever happened to anyone else? I also had a increase in vaginal discharge it usually comes and goes. I need some help. 5th answers gets best. Thanks!!!