I've recently been expiercing symptoms as if I have started my period but I missed my period I've been cramping and feel like my stomach is getting tight my lower back aches and I've urine more then usual and head aches come and go. I took a pregnancy test it came out negative though

I did go to the doctor but it doesn't seem like she was much help
All she said was it could be pregnancy and that I don't have a bladder infection
..

So I'm a little confused if it is pregnancy symptoms