... might see in other given rule that C - D - A. Now ... you know that for this rule to hold, you can't ... or after D; and another rule that B - C. Now you ...
One more question, as to the game you created, my first reaction is to get rid of B, because B hates two others; In fact, I always tend to get rid of the one that contradicts the most number of others. Could that be a rule of thumb?
O1-O2-R1-R2 is possible, but that is not the rule. The correct order (if this is the only rule) could be O1-R1-R2-O2. If you wrote down O1-O2-R1-R2, you could miss a possible correct answer.
If you have the time to take a full-length test you should. Then BR, and re-focus your study schedule on areas of your weakness. Don't forget to also keep your strong areas strong.
If I'm stuck on a game I come back to it last. Usually I find I just don't know how to set-up my diagram, so if I'm in that situation I look at the grab-a-rule question first to help me out :) Good luck!
You should not give up.. Do not forget.. there is always a bright side.. You can apply with your LSAT score of 149 for this year.. do VERY well your first year and transfer to a top 100 school your second year. There are always options.