I would recommend doing some no stirrup work. This will help improve your balance and your position, as there is less room for mistake when riding with no stirrups. What I’m trying to say is that without proper position, it is likely you will lose balance. You can also do some bareback riding and this does the same things as no stirrup work.
I know this probably doesn’t really make sense, but basically do some no stirrup work or bareback riding.
Hope this helps! 😄
Try lengthen your stirrups and just relax and breathe try do siting trot before cantering as not being able to do sitting trot will make it difficult
Hope this helps