Maybe you wanted to draw something special and found that you couldn't. You did it, but felt bad with it. These experiences are very important and precious. If it comes to drawing, our will is not of much use. This may be hard to accept.
Drawing happens on the right side.
If you want to read further, there's a very good book on that. Just let me know, I'll give you the title. BTW, send me your exercises. I'll see what can be learnt from them. Today I want to get you into something more elaborate, yet equally simple.