I was recently musing on the concept of "success." All us writers harbor dreams of making a living at writing, quitting the day job and being full-time authors. There's nothing wrong with that dream, and we should go after it with all our gusto. However, I know some writers for whom that is their sole definition of "success." If they aren't making their primarily living at it, they feel like a failure. I think that's a sad way of looking at it and a total fallacy.
If you are doing what you love, you already have a modicum of success because many people in this life don't. They have it drilled into their minds at an early age that maybe their passion is pointless or worthless and they simply give it up. So if you are still pursuing your passion, you're already on a winning path.
And the fact is that the majority of writers working today do not make a living at it. Does that mean the majority of writers are unsuccessful losers? I don't think so. For me, while I continue to pursue the dream of being a career writer, I am quite happy with my current set-up. A day joy that pays the bills and I don't hate and which allows me time to write. You never want to be stuck in a job that makes you miserable, so my advice is while you chase that dream, find a day job you actually like, and continue writing what you love. That to me is successful.
Now I know some writers who've said that by already considering myself "successful" in my current circumstances that I'm not as serious about writing as they are, or I'm not "on their level." Well, I don't even think in terms of levels, writing isn't a competition, but I'm damn serious about my writing. I just define success differently.