I have been practice Rancid milk for a couple weeks now. It took me about 5 hours before I could complete the sequence, now im just smoothing, refining, adding flair, and learning the performing side of it over the technical aspects. Its just such a fun trick its become my default!
Pretty much if you feel burnt out, back off, try something else for a while and I bet when you come back youll be better, closer, and more confident.