I've re-read the OP and the other responses.
It's worth also pointing out that your experience in the circuit phase of your training is actually quite normal. It takes that long. And each lesson can indeed feel as if you're not getting anywhere - you focus on the things that were wrong last time and lo and behold! things you were doing ok now mess up. This is because you don't have the brain space to learn lots at the same time. Only when a lot of stuff is automatic can you move on.
Circuit work is intense and hard.
You are expecting too much of yourself.
If circuits are getting tiresome (perfectly normal!) ask instructor if you can have a lesson going off and doing something else for a change. They should be ok with that if you explain your feelings. Get them to show you practice forced landings or steeply banked turns - that'll put a smile on your face.
If they are so inflexible that they won't do what I suggest, then you can be upset and take it further with the CFI.