The only way to be successful is to persevere. If you can’t pick yourself up, dust off, and try again then you have a very low chance of achieving all the things you want. Sometimes what seems like the path to get us to what we think we want is a dead end, and we have to back up before we can find a new path. And yes, that sucks and can be very disheartening, but most of us go through that, some more than once before finally getting to our goal.
Relative to your situation, I’m not clear what your goal is. Are you simply wanting a full time job with a decent salary? Because there are actually a number of those out there, even if they may not be glamourous or be more physical or a “dirty job”. I hope you understood when you decided to pursue it that an art degree was much less likely than most others to lead directly to a lucrative career, so to be upset about not being able to get a full time well paying job related to that is hopefully not a surprise. Similarly it sounds like you’ve discovered that your GPA means pretty much nothing once you leave school. So now you have to decide what you want. Yes, that may mean you have to change your expectations. Don’t fall into the trap of thinking you are owed a certain salary or position simply because you have a degree in something. Be willing to take the lower level role to get in the door, and if you are as smart and motivated as you say you are, you should be able to advance fairly quickly.