I had the exact same thing last night (though some were quite painful). I was on the verge of calling the hospital and packing my bags because it felt like labour! The only difference was that they weren't at regular intervals - that is what stopped me from calling. I saw my OB today and he said that it is 100% normal (especially for a second preganncy) and the only time to take action if it happens again is if you have an bloody discharge or if you are getting contractions that last 1 minute at 3 minute intervals.

It is super stressful - especially when we are so far along. Always remember to follow your instincts though and call your hospital if you are worried - it is so much better to be safer and sorry.