Ive been bringing my horse back into work after a long period turned away due to various issues. We've started doing a little bit more schooling recently and she's doing okay, a little rusty but its to be expected. However, she's seems almost incapable of cantering 20m circles. Whenever I ask her to turn away from the track she seems to not be able to maintain the canter and falls back into trot. When I ask for the canter on the circle, she bucks, not massively but enough to show she's not happy. She's perfectly fine trotting 20m's, serpentines and cantering large. She's very heavy on the forehand; and sometimes gets carried away and pulls like a train, so I'm wondering if its a balance issue?