Most times, after playing for 8 hours, my legs ache pretty bad...but I just take a break...maybe grab a bite to eat, and I can play for another 4 hours or more. The second day is a little rougher. Time flys when you're having fun.
I'm surprised you didn't get a wheel chair, and keep playing....where's your love for the game?....just joking.
I usually take it easy on leg work outs. Simply because your legs are working all the time. And they are supporting all of your body weight through out each day. Exercising the legs should be done in moderation. Unless, right before going to sleep at night. Then, you just have to manage to crawl into bed before falling on your face. Munch on a protein bar. It will help your muscles recover very quickly. Immediately after a work out, stretching lunges will help. But, it hurts a little.