Cramps but No Bleeding?

For about a week now, I've been having moderate to serious cramps, but still no period. It's been increasing in pain each day, but comes and goes throughout the day. Mostly when I'm doing something active such as walking long distances, or any sort of excercise, it increases quite a bit. My period is approximately one to one and a half weeks late, but I took a home pregnancy test and it came out negative. My period is a little irregular in the sense that sometimes I get it twice a month, but I've never missed a period. I've had early symptoms of pregnancy; very, very tender breast, decent amount of size increase in the breast, sudden weight gain, and fatigue. I haven't had nausea, or morning sickness, so I'm really thinking it might be something other than pregnancy. The month is about to be over in 3 days, should I wait to take another pregnancy test, or is it really time I see my doctor? I've avoided the doctor due to financial issues, so if there are any other suggestions, it would be most helpful. Thank you so much!