First time shooting (I presume) a wedding? I think you're being a little hard on yourself, lah.
As many have pointed out, photography is one of those things that's easy to pick up, but takes a lifetime to master. Well, maybe for most of us, even a lifetime may not be enough. But that don't mean we stop trying. I've been shooting since '88, and I still consider myself "OK" only. Nothing great. But it doesn't stop me from enjoying myself. My very first wedding shots were quite terrible, I think. Head cut off, arms missing, distractions in the background, foreground, left, right and centre.
Get the basics down right first. Get yourself one (and just one) good book on photography and stick with it as if it were a (insert name of holy book). Then experiment, ask yourself why you like a particular shot, or why you don't.
Look at the works of others. Don't overwhelm yourself with the technical aspects of the shot, exposure settings, etc. Just appreciate the images for its artistic content, and draw inspiration from them. Photography is an art, and much of it, you go by feeling.
Just chill, man. Takes time. Take pics, have fun.
