I had the same issue as you, wherin my levels were taking 20+ days because I was forgetting all my readings and only doing my reviews in my lunch break.
My advice is to pick two times 12 hours apart (for me these are 6am and 6pm) to do reviews and follow this guide, get ultimate timeline and ultimate re-order scripts installed, and respect the review intervals of WK and I soon found myself getting 95%+ in each review! Maybe hold off on leveling for a little while to make doubly sure you guru all your lvl 11 vocab, but otherwise you should be golden