10 years ago I'd have answered this question differently than I'm about to. If you love music and want to make it your life, quit your job. Period.
This is what was told to me 10 years ago, but a very well meaning artist I was performing with. She did exactly that, and she now earns a decent and secure living playing music. All the people I know who earn their money playing music, whether their income be $20,000 a year to $100s of thousands (and yes, I know quite a few doing that), all quit everything else and made music their number one. Anyone else I know, including myself, who put some other money making thing in front of music splits the income at best. Meaning they either wind up doing music as an avocation, or earn very little musically. At the time I was doing best in my life musically (touring and living mostly off music income), music was top priority. As soon as my day job started requiring more time, the inevitable happened. I'm off for the summer right now, and seriously reconsidering all I've done in the past 5 years. I may very well be taking my own advice here in a couple of months... music has always been most important to me. In the few months I have off here things (musically) are already starting to move into high gear, rather quickly too. Anyhow, it's a tough decision, but I think it's best to get clear early in the game.
Do you want a clear and secure path, a settled lifestyle, a wife, kids and storybook family most in life (not that you can't have a wife, kids and music)? If so, hang onto the job. Or do you want music more than anything else this world has to offer? If you want the latter, then make music your life. It's a giant leap of faith, but one that from what I've seen always pays off.
One important note, from what I've witnessed in musicians I've known over the past 30 years. Hard working professional musicians, who don't get involved in drugs, pot smoking, and heavy drinking, generally wind up happy and content with their careers as musicians. All the ones I know (who have been at it for decades) who ARE involved in the party scene wind up bitter. I can say that almost 100%. Some of them earn their living at it, but they're not fun people to be around or work with. And I wouldn't want to live in their shoes.