M.C.
I have read the other answers and just wanted to put in my two cents worth. Yes, you are starting labor. Probably a good idea to call the doctor and let him/her know. But, if you go to the hospital, they will send you home if you are not dialated a certain amount. My suggestion would be to stay at home as long as possible. It is way more comfortable. You will be hooked up to all kinds of things once you get to the hospital and moving around is more difficult. Congratulations, baby is on it's way!