I'm learning kanji quite quickly (well it seems so... I have around 80 now... which is only a drop in the ocean, but still... ^^) and I don't have too much trouble with vocab, but now that I'm learning kanji by myself and I don't have a class (no classes over summer ><) I am not learning anything new in the way of grammar. I haven't forgotten the really really basic stuff I learned at class, and I know some verb endings (past, conditionals) but I really wish I could be learning more of grammar as well as the kanji.