Aero, you are completely right. I know I have been making excuses ,and have been my whole life. Can you give me more details about how to adjust my mindset? And what kind of mindset I should have? i really have no idea.This right here. You expect to go to graduate school when you cant even keep track of the amount of credits your classes are worth. Grow up and get real. Don't even think about going to school until you've figured out a way to get serious about your pursuits.
To tell you the truth, I don't think you're even ready to go to school. Throughout your post you make these poor excuses: "The professor is rigorous", "this class is BS", "my friends failed", etc etc. Do you know how many people care about excuses: nobody who takes there work seriously. Granted, there can be teachers who enjoy tormenting their students. That is a reflection of their inadequacies and it should not translate into your justification for incompetence. Using excuses like these will lead you to failure, inevitably; no matter where you go, no matter what situation. In other words: if you don't accept your responsibilities, you will fail. Your experience with school should have made this very clear to you.
Assuming you have come to the realization I mentioned above, you must now accept your position and work to make BIG changes. For starters: it is absolutely critical that you change your attitude. Failure to acquire a new mindset and outlook towards challenges will result in a total waste of your potential.
Don't believe me? I can tell you about a friend who had a similar attitude your described above and he is happily living in his parents basement, mid 20s, no job, no girlfriend, nothing.
Once you have a new mindset, then it is time to go back to school.