Yeah, morse is a toughie because if you get mentally stuck on a character you will fall behind and start missing even more. But just memorizing the characters isn't enough, you need to be able to mentally relate the sound on the fly. It's really more akin to a language and you need to practice at it.

Honestly what I tended to do was pick up 80% of the characters and fill in the last 20% from context, just like filling in unknown words in a sentence out of context. And much like with foreign languages I was better speaking than receiving.