A long way to go

I'm a working mum and I've been practising spoken English online for one and a half year. My spoken English has improved, but somehow I feel stuck. I mean I haven't move on to the next level. I learned a lot of new words and new expression in the classes. I understand the words in the articles and conversations. However, I can't fluently use the words or expressions that I've learned. I keep using the same words that come first across my mind, especially when I'm doing the mock test.
I'm still struggling on the way of learning English. It's tough and it requires hard work. I will try my best with my pace. I believe that I can speak more fluently and more confidently in the future.