Hello!
Dang, you put in a good amount of work - nice!
I agree with what @snakker said about practicing linework. I think it would be very beneficial for you to go back and practice it.
Daily Photoshop for Digital Prod 1 assignment 1 - Pen Control (digitally or traditionally) from Term 1 Week 2 and
Daily pen control practice from Top 10 Drawing Exercises on YouTube (digitally or
traditionally) from Term 1 Week 3
Its going to save you a lot of time and make everything so much easier in the long run.
Never worry about speed. Accuracy is all you need to worry about. Artists get faster by having more knowledge and accuracy so it comes with practice and shouldn't be forced.
Also, what program are you using? Try playing around with pen pressure for opacity and line weight when doing the pen exercises. They can suggest a lot of form when used properly.
Keep it up! 
