Pelvic floor pressure is common. And it depends on the pain. I'm always in pain and I'm over 37 weeks- no preterm labor here. When in doubt, bring it up with your doctor. More than likely they'll brush it off as just lovely side effects of pregnancy.
if i were you,id be going to the doc now.just incase,its better to be safe.
on one of my pregnancys when i was around 6 mnths,i got cramps and alot of pressure on my lower abdomen and very bad back pain,also pains in my legs, as id gone through labour before i knew this felt the same.i went to the hospital and it turned out i had got some kidney infection or somthing and i didnt even know,but because it was left untreated my body just went into labour.well they caught it on time and kept me in for a week giving my steriods and stuff..
well just incase,you should see a doctor,just have it checked