I have a couple thoughts that have worked for me. I don't know of a "cure"..for me it's more like waves. I'll slump into a creative block and then feel like I slowly work myself out. Hopefully some of these will help you out.
1.)Step back- Take a deep breath. There's nothing wrong with you, you're just about to stretch as an artist. Take some time to meditate and think about why you feel the way you do. It it the style, or the medium? The story or concept?? There's a book called "The artists way" by Julia Cameron. It's AWESOME, and will help you with these feelings and so much more. Give yourself a set number of days to not draw. Get out with a friend or significant other
2.) Get a fresh sketchbook, whatever size you like or want to try and write the purpose of the book in the cover. I like to say things like "No one is allowed to see this sketchbook. There's no strings attached, no expectations, nothing. This is for me to explore.This thing should look like a war zone. I can copy artists work, steal, tear out bad pages, I can do whatever I want." When I start to get anxious about my work, I read the front page and remind myself that there's absolutely nothing to worry about. Seriously, this is your book. You don't need to show it to anyone. If they ask or start trying to guilt trip you, you just say "sorry. nope!" Start someone in the middle of the book. I even take a brush pen and make random marks on some of the pages as I go so that I don't feel like I'm "ruining" a clean page.
3.) Find a simple project you'd like to do. Focus on the enjoyment. Pick something you can finish, but make it simple. Example: I decided to take a simple one sentence story, and tell it in X number of pictures. I told myself that it was for fun, that none of it was for money, I could try however many styles I wanted, and that I needed to finish. For me, finishing it will mean printing the final work in a book , and printing all the thumbnails sketches on a poster..I guess it will sort of be a trophy to myself showing that I really can finish things, and that I am a master of my creativity; my creativity is not a master of me.
Just some thoughts. Keep us posted on how your're doing! Best of Luck.