Contractions.

So, first pregnancy here. I am 27+ weeks. I have been having contractions almost every say. My doctor said I'm fine, but I am concerned. My next doctor's appointment is a few weeks away and the contractions are happening more and more and becoming more intense. It started off happening every three days for a minute or two but then two days ago I had 5 contractions lasting about 30 seconds to a minute with 15 to 30 seconds in between followed by sharp pain. Called the doctor, she said relax and if it happens again tonight make a trip to the ER. Didn't happen again, but its making me very anxious. anyone else experience something similar?