what i'd do is, just keep on the positive side of the art . if people say 'i love your art' your art is good ~ the more u put yourself down the more it drawing wont be fun . just gotta stay positive and find ways to motivate urself like listen to music, or play a video game anything
If someone wanted to publish your work, then that means that your work is publishable by their standards. Commercially, that's all that matters. If you choose to do this professionally, avoid pointing our your faults to anyone else who can potentially use your work for some type of project, especially if you expect a big payout for it.
I had the same issue, actually. I am currently in art school but I was having issues with motivation to do art even before then and certain classes and assignments began to feel like chores. However, I recently reaffirmed my passion for illustration and the drive to create is slowly coming back. If you feel like you are being overwhelmed with projects and work that you are given, it might just be helpful to take a break. If you have no drive right now to create work just for yourself, you can take a break from that as well so you don't feel like you're trying to force something out of you. You can also try to temporarily find another creative outlet such as music or writing. Block and lack of drive is a thing that comes and goes, and this may be something that can get better with time. If that is not the case then it may be something else in your life and you might have to just identify what's wrong compared to how you were feeling previously and attack the issue head-on if that's possible.
Also, in terms of using reference or tracing and the like... it's a bit different with commercial illustration. Assuming that the reference isn't something copyrighted or easily recognizeable (or even completely original; taking your own photographs for reference is a plus since it's entirely from your perspective) an art director or editor would much rather see a finished illustration that utilized reference to create the most accurate picture possible than if you didn't. Just try not to use it as a crutch, and practice enough that it can come naturally enough that you're not relying on it completely. Source: Professors of mine who have been working in the industry for years.
I wish you luck, and I certainly think you're capable.
I second all the above for motivation. It's hard to see your own work as good, but if you've been commissioned, this person obviously thinks your art is good. To that note: your art teacher is one person. I know we're supposed to treat teachers as the gatekeepers to what is right and good, but especially in art, teachers are just one person. So what if this teacher didn't like your art? This teacher clearly didn't know how to actually teach, since "go deeper" is about the most useless piece of advice ever given. My question is when you talk about your "copied" art VS your "drawn from scratch". Are you not using references for the freehand drawings? Freehanding is hard and anatomy is complicated. If you're looking for a pose, don't be afraid to look it up on google and stockphoto. Seeing how "real" bodies move and sit is a huge advantage and most successful artists use multiple references for each piece. It's not copying, it's referencing. You might need to sit down and just bang out a few of these pieces just to prove to yourself that you can. Even if they're awful and you hate them, e-mail them to your friend and tell them they're WIPs, see what they think of the art, I bet it'll be good. Update/redo it if you need to, but I think you need to just prove to yourself that you can do them and that other people like them. You're gonna be fine, don't worry. *internet hugs*