I agree that u should persist as we did the whole taking dd out of the pram thing and now she is to heavy for the baby bjorn...i also found that sometimes she was just tired so i started to put her wrap in the pram with her n covered the pram...she now snoozes when she wants n if she is grizzly i give her a different toy or a rusk...i know its so hard to push the pram when ur baby is crying and your trying to look calm about it but try to persist or alternate between pram and sling? they sure get heavy to carry around as they grow.
Have fun