spd pelvic girdle pain help please?

Rose • Hiiiii
I'm 21 weeks pregnant and it is just starting to meither me at times today is especially bad day I knew it from the moment I woke , I've taken it easy all day but my daughter decided to be a pain and hang of my other daughter's stroller on the way home from school half way up a steep hill , dragging the pram up the hill with her hanging on i felt a ripping extreme pressure in my pubic area but couldn't stop due the path being full behind me ! I stopped when I could but now I'm in so much pain especially getting up from sitting and walking the stairs in fact anything that requires me to lift my leg or move my pelvis in an a not straight way , what can I do ? I don't know how to ease the pain I have so much to do tommorrow too so I can only try to rest it this evening :(