It might have been hard, but you should be proud of yourself for having completed 50mi. That was a big jump in millage, so good for you! Take some time to recover, some easy rides, and you will be ready to slowly build your millage up. And yesterday, having been off the bike for over week (partly b/c I had gone hiking in the desert, sand, and my calves were so shot I could barely walk) I got on my bike and rode 50 (my usual "long" ride) and while fun, it was really hard! 50 is no easy challenge!