Well, since I'm learning Spanish and I always forget all the words I need to say when talking to native speakers, I woud say yes I've felt that I forgot everything that I've learned. What I did was to ask my speaking partner directly what the word is and how to use it.

You could try writing words or phrases on pieces of paper and sticking them on the walls in your home. That way you're constantly reading them. You can add and remove ones each week or when you've memorised them so you're constantly progressing.

Thank you very much dear Matt and Janey