How can I keep learning English for long?

I always want to learn English and improve my language level, but I couldn't keep it long.Learn for 3-5 days,and I would stop learning, and a few days later ,someday I have to use English ,and I learn it from the beginning.I know it's not good.So is there someone who can help me for the problem?And I think if I can get rid of this ,I can learn English well.