It seems that other members have already provided some of the details, so let me just offer some general ideas.
The inconsistent study plan prevents you from finding a rhythm. This will be difficult, but spend some time figuring out how to develop a consistent study plan for everyday. Sometimes you won't be able to follow the plan perfectly, but you at least need one to keep focused and dedicated.
Another problem might be GMAT fatigue. You studied for awhile now and even attended two courses. If you feel a little exhausted mentally, then take some time off. Once you start your new studies, though, break time is over. At that point you simply can't afford to take any more days off.
I assume that you have the Manhattan math books (since you took the class). If so, re-read the math books and skip the end-of-chapter questions. Complete all of the OG problems alongside the
MGMAT books and make sure to fully read every explanation.