Hi Artsy!
I was an illustration major in college and I am essentially doing the same thing today but for a corporation.

What medium do you prefer? Painting? Photoshop/Illustrator? Or do you like working with text layout?

You can make a living doing any of what you mention-- art CAN be the main career right off the bat, it doesn't have to be Starbucks plus painting.

I would suggest doing what you love to do and making money will follow. I think the key is to just keep at it, even if you get discouraged. Persistence has been key for me to makre this a career.

Hope you find your bliss! I'm an INFP too BTW