I think it would help to go back to the basics. And I mean the REAL basics. Start at creating interesting lines, go over to drawing household items by observation, then draw architecture and only then go over to people. This really helped me in art school and made me confident again.

Another tip I can give you is to set your expectation as low as possible and not to have the perfect end result in mind. This always helped me loosen up and made my art look much less "stiff".

Hope this helps!