talismaaniac, you are not alone with this problem (when I do not understand the CR argument, my brain keeps repeating it without comprehending anything). Most of us suffer fro the same problem over time.
This is nothing but lack of concentration. If, at first attempt, we don't understand something that is written, we lose our concentration and our mind start wandering here and there while our eyes are still rolling on the text. But because our brain and eyes are not working on the same thing, we don't understand what is written at all.
I am no expert, but we always have advises to give

.
Fun apart, what I understand we all have to do is to focus on accuracy first and time later.
If you have some time (2-3) months for your GMAT, don't use clock for next 15 days and try to work on questions to increase accuracy. As you practice more and start understanding patterns, your accuracy will increase and than you can start using clock to time your answers.
You can also try to take a break from CR for couple of days and take up SC / RC. And when you come back to CR you would be more refreshed and confident about CRs
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