>>33
Have you tried spaced rather than massed practice? Have you considered memorizing and refining understanding such that any forgetfulness can be compensated with derivation (hinted at in >>29)? Do you make sufficient use of visualization in understanding? Do you attempt to understand things from multiple perspectives? Have you considered using the method of loci?
Maybe mathematics is just not for me and I would be better to do something that is more fitting my brain.
Very few people are perfectly oriented towards the study of mathematics, even most professional mathematicians have flaws they have overcome. You should not give up after finding a single flaw, especially given memory is one of the easiest of our fundamental capabilities to improve.