I need some motivation.. Pls :(

ONE CRITICAL THING. In gmat club, there are question banks based on topics in the forums. Download them and focus on each (algebra, geometry, etc). Make sure you can solve the typical qtn types quickly and efficiently before moving on to the next topic. Do not focus on OG right now which doesn't break down the question into different groups or question banks that don't segregate the qtns into their respective topics. Solving 100 rate qtns in 2 days will eventually drive to you what are the best ways and short cuts to solve this kind of qtns instead of 100 rate qtns mixed with 900 other type of qtns over a month. Once you finish a section and are confident, move on to the next topic you're weak in.

If you have a strong understanding of how to do the basic 600-700 level PS questions and can solve them in time, you're practically guaranteed a mid 40s in quant which gives you a much higher probable chance of getting into the mid 600s.

With your fundamentals currently so weak, it doesn't make sense to take CATs or a complete Quant section as you only have 2-3 qtns on each subject. Once your basics are down using the above method, then try the CATs.

Also, it sounds like you have a mental block when it comes to translating english into math. You say you can't do it, insist you can't and obviously you won't be able to. Take a deep breath and see that its just a matter of cutting things into smaller pieces. Look at something like this.

Tic is the 3 times the average of the sum of 100n and the median of (5, 10, 15). Its a pain in the ass, but break it down into:

Median of (5,10, 15) = 10
sum of 100n and 10 = 100n + 10
average of 100n + 10 = (100n + 10) / 2
Tic is = 3 x (100n+10) / 2

approach from the back and write down on your scratch paper 1 by 1. To get this shouldn't take you 15s.

Or A does x things in 6hrs. So his rate (things done per hr) = total things done over total time = x/6

After you do a 100 rate qtns, a 100 ratio questions, a 100 geometry questions et all, you will figure out a template to get your answer quickly. 3 weeks is a long time if you can focus exclusively on GMAT preparation. Don't panic and think you can't do it. Remember, smart people are just better trained chimpanzees.