Confused

Maybe someone can help me figure this out. Okay.. My last period was May 19th and it is now July 23rd. Around the time that I was suppose to have my cycle in June, I had cramps for like 2 to 3 weeks but no period. The cramps were a lil different than period cramps like lil twinges on the left side. I've taken a pregnancy test the day of my missed period and up to 3 weeks after my first missed period but they were all negative. I've had some nausea without vomiting and moments where I'm lightheaded and dizzy. Here lately I've been having some sporadic small pains in my breasts. So here I am now two 2 cycles late and confused. Any ideas of what is going on? I'm supposed to see my doctor in about a week so maybe I can get more answers.