I didnt feel them with DS but i started getting them around 22 weeks maybe once or twice a week...my belly would drop, get really tight, my heart would race and id get extremely breathless than after i sat down or took a couple of good deep breathes id be ok.
Now i am 32 weeks and they are coming just about everyday usually when im trying to tidy up or do shopping anything a bit more strenuous then usual...im sure ive scared a few fellow shoppers while im out and about grabbing my belly and breathing deeply