You can do it!
Nah. You’re not a bad student at all.
It’s just a mix of technique and discipline 
There are several strategies to keep on track. Here is one of them:
First step: Establish a daily objective. Select a fixed number of maximum reviews to do every day and don’t let your apprentice items to go over 100.
How to do that?
Second step: Start by learning 15 lessons every day and stop when your review queue surpass the number you selected in first step.
This way you can get to Level 60 roughly in two years.
Another suggestion is to include yourself in some Ladder of people doing WK to get some motivation. Let me recommend you this one:
I have the bad habit of not doing wanikani on the weekends. Every monday I get back to 200-300 reviews and clear them up in about an hour.
Depending on how long it has been since your last session your 500 reviews could much more time. 
You could try setting a timer and when it goes off wrap up the review session. When I’ve been particularly overwhelmed, a 15m timer has helped get through some reviews even if not all of them.
lately that happens to me too. no idea why since my weekends aren’t that busy.
also since during the week my reviews are mostly done before 10am and i most likely won’t be functional before 10am on the weekend, my motivation plumets as soon as i open the app 
Nice that I am not alone in this
I usually do my first batch right before work, the second batch in my lunch break and the third in the train on my way home. On the weekend I just dont have that routine and I have a 1 year old who is also keeping me very busy. I am sure I could squeeze in some WK for example when he is sleeping but I think its more important to rest during that time 
I feel that XD