Strain below bump?

New Mama
Is anyone feeling strained or pulling as if there are strings from the bottom of your bump to the top of the groin being over stretched?  Happens most when I get up after sitting for a bit.  I can walk it off and am fine if I stay up (went for a little hike in the snow yesterday!) but am a little worried to find out how much worse it can get - I'm only 28 wks tomorrow.