My new gerbil stopped moving?

today my boyfriend and i bought a gerbil. we already had a tank, so at the shop we bought bedding and a bag of food. but we forgot the water bottle, so until tomorrow i put a shallow bowl in there half way filled with water. everything was fine for the first few hours he played, ran, ate, pooped but i didn't see him drink any. after my bf got home from work he got him out and he went crazy (ran around the bed for 10 minutes straight) then all of a sudden he stopped. we began petting him and he just sat there with his eyes open. i placed him in his tank thinking he might be sleepy but he still didn't move. then about 15 minutes later i touched him and he jumped up and started acting some what hyper. did we do something wrong? is this normal behavior for the first day home? thank you for your time.