It really helps if you have confidence in your horse and trust her/him not to go into a bucking frenzy. I trust Vida as much as I have ever trused any horse. If you don't have that then its best to not overdo it till you know your horse is ready for it. Its better to be safe then brave Has Sonny ever given you reason to fear cantering?
I do know exactly how you feel though.Since I just recovered from a bad fall. Before that I loved to go fast, now I get a little "oh no, oh no" voice going when she even tries to pick up the pace. I'll get over it in time. Don't beat yourself up too bad, your not alone. You'll get there I just need to do it in a place with a soft landing
I just went through that phase to! I was afraid to canter when my instructor told me to canter I would have a pound in my heart. After last weeks show I got first place I am very happy. Just canter if your afraid I did now I feel great! Keep Trying