Hi,
Don't be discouraged and don't be hard on yourself.
Drawabox.com is free, it starts from the fundamentals, it is a course I am going to do myself. For colour theory off the top of my head I would say James Gurney, he has a couple of books and Youtube.
I would say draw/paint from life as much as possible. Also try using just a pen, it is kind of scary as all the mistakes are there but apparently it is supposed to develop skills although personally I haven't found that myself yet...
