Help

I am 18 and have done arrays, basic recursion, sorting, binary search,basic linked list(insertion, deletion etc). I have tried leetcode problems related to these concepts, only about 20-25 and not been am to do most of them without any help, i might have done like 4-5 by myself. It's been 2-3 months, I have seen no improvement, like literally nothing.Do i study all data structures and algorithms first then start leetcode ? Please help stressing out and I feel dumb.