Really before you can consider yourself a professional artist, you're going to need to be better at defending the value of your art. That only comes with time, attitude, and dedication. You have to be your own biggest fan. If you don't know what's great about your work (even if it's just one small thing) and you don't love it intensely at some level, no one else will.
I know some of it is great, some others not so much but.. it's like anyone right? you can't be inspired everyday and every second of the year, especially when you're trying out a new technique(school). Personally I have great pride in some of my most recent works and I know i'm pretty good at human anatomy and rather good at lighting too, but clearly not to a profesional level such as you. I do my thing, and I try to improve where I can, when I can. I also have pretty heavy ethics regarding art. Sometimes compliment shower on me.. but i just don't seem to be able to take them, i'd rather have good critics to help me improve than a comment just saying it looks good. You art is inspiring and breathtaking and I hope to one day prove myself to be a profesional artist such as yourself thus why I study and learn and do what I can. All in all I have yet to find my style but I know it'll come so I don't mind so much