Now this is something I struggled with for a while. And while I'm still on my journey of improving my art (it never ends btw, unless you want it to.) I've realized that people work at different paces.
It's ok to take a break when you get frustrated. I've found that a good way to implement practice into my workflow is by first getting a drawing that I see needs improvement, I locate the main flaws, and I do maybe one or two studies on it.
After doing these studies, I take a break from the grind, and I simply draw what I want. It doesn't have to all be studies. Also, don't be afraid to trace, that's how I first started understanding proportions and form. On that same note, do lots of reference drawing and change it up! If you draw from reference you don't need to do it entirely to picture.
On an ending note, remember, if it's actively making you dislike doing art, stop doing it. You can find ways to improve your art in other ways.
