I feel the exact same way, especially on days when I’m at work and have a constant flow I need written down but can’t take the time to do it.
I've always been aware that being a writer may never be my only job. I never planned to write fiction all day. I even lost my habit of writing a lot over the weekend. I work best by writing little, 500 to 1000 words a day, and when I'm inspired. That's why it takes me so long to write something. But it must be because of the market of my country. National authors aren't well accepted, most of the books sold are translations, there are only about 10 authors who really manage to sell well (not necessarily the best ones...). And yes, I think it's silly to leave work to become a writer before getting a place in the literary market. It's difficult, it doesn't work for everyone, and it's always good to have financial security. But maybe that's because I'm a woman, and from what I see, most of those who devote themselves exclusively to writing (even though they've never published anything before) are men. And this is just my observation.
This is a tough question. If I get you right, your question goes deeper than talking about the craft of writing; you´re aiming at what would satisfy you as a person. Where I´m at is this: I´m going to try, wholeheartedly hustle at different things. One of them is writing. If I gain traction, if I find that it´s working, I know that it´s right. But there does come a time when I find that I just don´t have the intuition or background in a skill, so I adjust my expectations for what I can achieve at it.