I've been drawing since I was a kid. I have been really bad at actually studying art. I used to study (unintentionally study) all the Zelda pictures from the Zelda game manuals as a kid, I drew all the pictures I could find in them. Apart from that I only picked up actual studying this year, else I've only been drawing what ever I've felt like. You sure learn from that as well, but I highly reccomend both studying and focusing on personal work to get a balance.
Of course, I am doubting myself right now. Do I really have what it takes to become a professional artist? I doubt it, that's why I am focusing a lot on 3D modelling and animation right now, because chances are bigger that I will get a job. Still I keep producing art because I really really want to one day work as a professional artist, and giving up is the last thing I will do. To become a professional it requires a lot of studying, and by a lot I mean A LOT. But you can start from zero skills and still become a professional within only a few years if you are really dedicated. I've improved more these past 2 years than I could ever imagine, but if I had spent more time I could have done that within probably half a year.
Also a tip is, forget about "having to be in the mood for painting". That's bullshit, if you want to become a professional you should paint no matter your mood, because painting would then be work. And you cant skip work simply because you're not in the mood.
So yeah, my advices maybe makes you feel even more down because I'm very bad at giving advice, sorry man. But seriously, if you really fucking want something. Go get it.