Lydia:

It sounds to me like you have high aspirations (which is great) but an inner critic with the warmth and understanding of a grumpy drill sergeant who hasn't had morning coffee yet (not so great!) and I suspect, a lack of confidence in your abilities and low assertiveness?
I have the same combination going on, and it does lower self esteem!
Kudos to you for doing something you enjoy, treating yourself kindly. That's an important antidote to what we have going on.

Here are some sites I am reading which may be helpful to you too:

http://www.self-esteem-experts.com/s...ctivities.html
http://www.doorway-to-self-esteem.co...ctivities.html
http://www.about-personal-growth.com...criticism.html