Rest days aren't a bad thing in my opinion. Someday's I fell like utter crap and I hit the gym and get really crap results. I normally just leave and scuff my feet like a 5 year old. I hit the gym the next day, well rested and having the day before's events etched in my mind, I smash the gym to bits. Pride is restored.
Some days just suck arse.
Its a hard pill to swallow but its true. If you read my log you will see when I hate life.
Also we all grow at different rates, get used to that idear. Some guys a 6'4", some guys are 5 foot nothing.
Keep lifting, Keep eating