Terrible sleep

Pleeeease help. For 3 weeks my 8 month old has been sleeping terribly. I am exhausted. He wakes up in the middle of the night and just won't go back to sleep! He will crawl around to find a comfy spot, but he never finds one. If he starts falling asleep, he will toss and turn like he can't get comfy. This goes on for like 2 hours, and I'm constantly having to soothe him back to sleep the rest of the night. What is going on???

He is on a 2 nap schedule, getting around 2 hours of sleep during the day.