My baby (14 weeks) used to sleep so well at night but now he wakes up every 1-2 hours!

At one point he did 6-7 hour stretches. Then it got down to 4 hour stretches. Last night was the absolute worst. He woke up every hour! Help. What do I do?

His day naps have always been short. Mainly 30 minutes on the dot and then I have to rock him back to sleep for the remainder. But his nights have always been good. He would only ever wake up to eat. Now it seems like he wakes up just to be held.