I just failed my major prereq (Physics), feeling extremely depressed.

@LeroyJohnson are you failing it because you don’t understand the material or due to some other reason? I don’t want to sound discouraging, but if you can’t pass your major class for the second time, maybe it’s time to think about a different career path? Upper division engineering classes will be much more challenging than mechanics, and most of those classes will build upon the material from physics I, II and III.
Not everyone necessarily has to become an engineer, a doctor, or a lawyer. It’s great to have ambitions and dreams, but you need to be realistic about your abilities. It’s a common misconception that a degree in engineering is a key to high-salary jobs. The truth is you can be an artist (not that art is easier or anything), and if you are ambitious enough and good at what you do, you will be making just as much (if not more) as any engineer out there.