Duude, I'm a little late to reply to this one as life has had me way too busy for my own good, but man, gotta reply
First off, I was told very early on that art is a bit of an emotional rollercoaster so I guess it's kinda normal for anyone doing art to second guess themselves now and then. Sanest thing I think is to acknowledge it, learn from whatever constructive self criticisms you may have and move on - keep creating. Also, that drawing doesn't suck XD
Getting some serious islamic ruins with scifi or mysterious fantasy vibes from this architecture.
You're doing a lot of awesome work! I wish I had your level of motivation to do anything perspective related. XD
cheers