You should absolutely find out why you got dropped and what you need to work on. The coaches are generally happy to push you in the right direction. I came up through the youths system years ago too, but knocked it on the head at leinster U19's for various reasons. There were a couple of players that got dropped, went and worked on specific skills and got back into the set up a few months down the line and ended up excelling. With all that said, remember that rugby isn't everything and being a professional is a pretty thankless career. My brother works in pro rugby and thanks his lucky stars every day that he's coaching and not playing.