I cut a few of the roots around my tree. My tree is now in shock: the leaves are curling and it's losing some of them. The tree itself is drooping.
Is there anything I can do for my tree?
Water well and frequently - you haven't said how large/old the tree is, nor what variety it is, but if its all wilting, I'm assuming it's not a large tree. Difficult to be precise about how much water and how often without further information, but you have cut its water uptake roots (so to speak) so supplying plenty of water for the next 6 to 8 weeks should help the situation. Nothing else will.