Crankin, have you read "Bicycling Bliss" by Portia Masterson? There's a lot of good stuff in there about riding for health. She teaches about breathing, form, and techniques to keep you riding without injury.

I'm concerned about you feeling depressed by how fast you ride. I think you're awesome, and I know from reading your posts what you went through last year. You've gone through a lot physically, and you're still riding. I want you to keep going. A lot of people think going faster is "improving" when really, they're damaging themselves, and shortening their riding longevity. In the long run, you want to be able to ride your bike for many years to come, and be healthier from it. That's the point, not to compromise your health for speed.