Braxton-Hicks?

So today I'm just sitting here at my desk minding my own business when all of the sudden I feel this immense presure exuding from my belly! It was the weirdest thing ever. I got up and walked around a little and it went away after about 15 seconds. Of course it kind of concerned me, so to GOOGLE I go. Found out that the symptoms I had sounded just like Braxton-Hicks contractions. But BH don't usually start until 20 weeks (I'm just shy of 16 weeks), so I was on the worried side. When I went home at lunch I used the doppler and listened to Whatsit, and he sounded just fine, so that helped put me at ease. When I had another one after lunch, I called my doctor. The nurse said that as long as they aren't coming regularly or more than 4 an hour, I should be okay. Just to take it easy and call if I felt concerned about it.