What does reaching a bottleneck mean exactly?
Looking at it from a different angle, it could mean, with all the efforts you have made, you now have successfully filled up the bottle. It means you have outgrown your existing teachers, learning techniques and language environment. So, just maybe, you need a better teacher? better ways to learn? and more opportunities to use the language? It means you need a bigger bottle!
Anyway, it's not a time to give up, but to celebrate and charge ahead.
Happy learning : )