Your child's drive to master standing and walking has probably upset his daily routine — including his sleep schedule. His once-predictable morning and afternoon naps have become less dependable, and he's probably waking up more frequently at night. He may spend his crib time moving up and down instead of sleeping, and that's okay. Eventually, once the novelty of walking wears off, your child will return to a more settled state. Until then, keep putting him in his crib at nap time, but don't worry if he doesn't sleep.
At night, sleep disruption is even more likely. You can help your child get back to sleep by reacting calmly and firmly and reinstating all the familiar rituals. Give him about 10 minutes to go to sleep on his own. Then go in and pat him softly to reassure him you're there, and leave.
Eating patterns may also be disrupted. Your child may eat next to nothing at one meal and more than you do at the next. He'll balance it out just fine as long as you don't make a big deal out of it. In between meals offer high-energy snacks such as a bagel with cream cheese.