I am breaking down.

first of all I understand everyone studies differently. But I just can't figure this out anymore.

I used to think that if I take every question that I got wrong and write a 5 page explanation on how every part of it works and why I got it wrong I will be fine. I thought I would never fail this exact question, never again, because I now understand everything.

Guess what - I come back to the same question just 2 weeks later and I have no clue how to solve it. Again.

I have 700 right now and my quant is never above 48. I need to be 50-51 for my target schools.

I read (and took notes from) all 5 MGMAT books on math - great foundation, no question. But that's it - I don't know anymore what to do. Do I try new questions and make 5 page explanations again? or just flashcards? or just nothing? Should I aim to complete as many questions as I can? Should I aim to memorise every single one I did?

I can study 5-6 hours a day and combine this with full time work that's not a problem. The problem is that I am lost and don't know which direction to go. I feel I am about to break down.