sorry for so many posts today but I have a question, I actually feel silly for even asking because this is my third baby…

sorry for so many posts today but I have a question, I actually feel silly for even asking because this is my third baby but this pregnancy has been nothing like the other two and sometimes I feel clueless! anyway my question is: I'm 30 almost 31 weeks and decided today I needed to start working out (nothing crazy) and now I'm worried I may have started labor.... (god that sounds dumb to me) I walked half a mile and did squats, leg lifts while laying on my side and used light weights to work my arms (I've been pretty lazy up till now) and I've had several bh(?) contractions, feel a lot of pressure in my bottom (baby Timber likes to get way in my back and real low lately) and an achy real uncomfortable pain in my pelvis. am I just crazy or could I have started something on accident?