Thanks you two. Tia isn't dragging her leg, she's holding it up, that was one of the signs that I thought meant it wasn't a fracture. There doesn't appear to be any swelling either.

Anyway, we've just got back from the vets. Poor little Tia was so scared, she peed herself when the vet tried to examine her and she kept trying to hide in my coat sleeve. She's had a painkiller injection and we now have a four day anti-inflammitory solution that we have to give to her orally. Other than that she needs a lot of rest and restricted exercise to stop her over-using the foot. The vet thinks she's either pulled a muscle in the sole of the foot, or she may have even hit her hip bone causing the leg to be too painful to walk on. Either way, these things have to take time to heal themselves but I hope her recovery is as stress-free as possible for her.

Right now I have all the lights switched off in my room to make Tia think it's night-time and that it's bedtime, so I'm having to get around by the light of my laptop!