This gets brought up every so often. If you search around the forum, you’ll find threads like
WK is a kanji tool that covers quite a number of useful vocab. But you’ll have to work on grammar, further vocab (WK doesn’t always focus on the most common words, since it focusses on teaching you readings), and basically everything else outside of WK. 
It took me a while to get in a good learning routine with WK before I could properly flesh out my studies, but it were those other learning resources that got me to be able to use what I learn with WK. If I did WK alone, I wouldn’t be able to use any of the things I learned, and I’d be forgetting it all again.
Take some time to get used to WK. Get a habit in place that you can spend every day learning. WK lessons and reviews will become something you’re used to, and then you can expand to include other proficiencies as well. ^^