First, don’t take me too seriously on the matter, as I’m probably not better than you, but still I can share what I learned.
Drawing probably doesn’t help much with topology. You still have to learn how to create the right topology. But if you can draw something, you would know how the flow lines are running, which allows you the plan the topology very early, so you don’t have to change it later. The same is true for proportions. I find that I can judge way easier whether proportions are right, when more details are added. But then it is more work to fix it, as you have to shove more vertices around. I experienced artist seems to be able to do it the other way round (and then wonder why noobs always start detailing too soon).
For me the first relevation was, that I actually knew nothing about anatomy. Had to learn how the important facial bones lie, how iris patterns look, that there is a sternocleidomastoid muscle which only becomes visible during certain head orientations and so forth. But this is all just factual knowledge which can be learned and looked up.
More difficult is proportions. It helps a lot to put reference images behind your model when learning. Unfortunately one runs into a 3D issue with that. Easy to work with is having a front view and a side view image, but that is not the whole truth. It doesn’t tell you how oblique surfaces run.
Also human perception is very sensitive to noticing that proportions are wrong, but without training not in which way exactly (so aligning meshes to reference images requires pinpoint precision). There seems to be a certain kind of way to look at things, which artists have, but I have not, to easily understand how proportions need to be changed. I assume drawing makes one learn that just as well as modeling. That is probably to main reason why people who did that before starting with 3D make way faster progress.
I guess the next step for me is to learn how to create the desired appearance. A certain kind of face with a certain facial expression (without just doing an exact copy of an image).
I find toplogy less of an issue after a while (despite despairing over it at first). It certainly tends to twist one’s brain (often at the beginning, but later still occasionally). What helped me is to first figure out how it should be (where undisturbed edge loops/flows need to be), then draw these with grease pencil. Then it becomes easy to see where poles need to be placed.
In any case, I would also encourage you to continue. Don’t forget that on the long term practice beats talent 
. I can spend over a month on a single character and It still ends up pretty clunky.
I actually feel I have a pretty good grasp of Blender itself, but yeah I guess the “art” part is whats tripping me up.
