Painful Braxton Hicks

This is my first pregnancy so I have no idea what to expect from contractions and I know it's different for everyone. I'm 33 weeks and 4 days and have just started experiencing Braxton Hicks, they've just been uncomfortable pressure, not painful.
I'm a licensed veterinary technician, so I'm on my feet a minimum of 8 hrs a day and my job requires a lot of bending, lifting and wrestling less than cooperative patients. I work in an ER/ referral center so my days can be really stressful.  Today I overdid it and I know I did but my sometimes my job presents situations I can't avoid.
After we had a really tense 30 minutes with two patients I started feeling that uncomfortable tightening. Within an hour they progressed to a short 20 second rolling pain that continued for about 15 minutes. I had to breathe through some of them because the pain was pretty sharp. I haven't had any bleeding or anything like that and they did stop. I drank some water and a Gatorade and sat for a good 30 minutes when they started. When I got home I put a heating pad on my back and I feel much better now.
My question is, is it normal for strenuous activity to stir up some intense BH contractions? And at what point should I call my Dr? I know I probably should have called her today but I'm the kind of person whose arm has to be falling off to worry me, and I wasn't sure if I was over reacting. 
Everything I've read and been told says to call when you have regular contractions lasting so long in such and such time frame. But this was more like continuous waves, with no breaks in between.