He was doing really well, sleeping from 4-5 hours for the first part of the night, then wakes up to eat and sleeps again for another couple hours. Then last week he set a record and slept for 7 hours before waking up to eat. And that was it. He's been a bad sleeper ever since Thursday, waking up every few hours and very hard to calm down. He's almost 10 weeks. Could be be teething already? Or could this be a growth spurt? I'm just so exhausted.