Period question!

I am two months late on my period. I have taken six pregnancy tests at different times. My last one was taken today and it was still negative. There wasn't a faint blue line, there was absolutely nothing there. I am 23 years old and had a cyst removed from my ovaries about 5 years ago. My periods were normal prior to this. Could it be another cyst? Has anyone else had this problem? I have been trying to conceive for nine months with no luck. I think it's time to see a doctor but I was hoping to talk to someone with the same or a similar experience. Thanks in advance!