We had to put a bolt on the fridge door because our previous dog could open it! He was very greedy.
Hope you've eaten something since the original post, Mrs J.
One of my Jack Russells had a cruciate ligament injury many years ago, vet prescribed rest and anti-inflammatories and he recovered well. Getting him to rest, especially once the injury had started to recover, was the hardest part!
Essential oil of lavender will help her to relax.
Anxiety like that can form a vicious circle, the more cantering seems a big issue to her the more anxious and less relaxed she'll be. This probably isn't the best time of year to suggest this, but would it be worth seeing if she could canter out...
Strangely, mine has only just started eating hay this past week! She only eats hay when she doesn't get enough grass, so the good grass must have been eaten...