I'm 39 weeks pregnant and I have had this constant tightness in my belly but I don't really have any contractions just cramps... when I went into labor/delivery last week the nurse said I'm not dialated and that my contractions are 5-20 min apart but I didn't feel any of the contractions...

We really can't tell you if you're in labor or not. False labor and real labor feel very much the same, which is why many women go to the hospital only to be sent home because they're not in labor.

If you feel that you may be in labor, go to the hospital. Better safe than sorry.