My experience with learning Chinese is that you progress to a certain level, then plateau, figuring your are pretty good, then you realise you are crap again, work ahrder, learn more, setle down ....
Sort of like swimming in the ocean - first of all the waves are rough (near the shore), then they smooth out a bit and you figure, this is good, then you move out further and, bloody hell, then waves coming at you are HUGE, you get through that lot, it smooths out again until the next rough patch. And so on!
Jia you!