Don't be so hard on yourself - all of us started in the same place, knowing nothing about photography. Just work on improving, and things will get better. As for not letting those see the light of day - how were you going to figure this out any other way?
You are limited by your tools, although I'd say that the limit on the D50 is higher than you perceive. I have a very similar D100, and while it is clearly nowhere near the equal of, say, the D3, it's definitely capable of quite a bit. Finally remember that a noisy image can be at least partially addressed in post processing. A blurry one can't! So turn up that ISO and get some sharp images. Once captured - especially in raw - you can work on them later, returning to them if necessary. I've gotten some quite nice results out of 6- and 7-year old files that I only now have the software and/or skills to address.
As far as the dog's dinner... some dogs seem to have rather nice dinners!
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!