Hi
She sounds a bit like my 10 year old! Claudia has bursts of confidence (almost over confident at times) then something, might only be insignificant, will happen and she goes back a stage or two.
I simply go back to basics, i.e, leadrein if necessary, or walking only, perhaps only introducing trot just for a couple of steps at a time.
This way, we seem to progress in small steps instead of taking two steps forward and one step backwards!
I find it quite frustrating, cos I know that once she 'gets over it', she is fine.
One example is this - she was quite happy to canter, bareback and pony only wearing headcollar and lead rope around the field, the next day we went out for a quiet walk, pony spooked, she fell off and was terrified to get back on! I made her get on, then get off a couple of times, and then promised her that I would hold him while we walked home. By the time we reached the field, she was asking if she could take him in for a canter!