First full night and constant crying HELP

Elliott was born almost exactly 24 hours ago do tonight is our first night. He had been crying every 15 min since about the time the sun went down. He was so easy today! I don't get it! Ive heard that they don't want to sleep at night but is this normal? Literally every 15 min? And it's always crying and I don't know why. Checked diaper, fed, snuggled, doc says he's healthy... Nothing helps. He just cries himself back to sleep. Any suggestions moms out there?? I'm worried about him.