Sleep schedule completely destroyed - 4 month old waking every 2 hours

So we had a pretty decent routine going with our son until last week. He was doing 4-5 hour stretches at night, we were managing. Then he turned 4 months and it's like someone flipped a switch. Now he's waking up every 2 hours like clockwork. I'm running on fumes here. Wife is EBF so I can't really help much during the night feeds, which makes me feel pretty useless. She's getting frustrated with me falling asleep on the couch at 8pm when she's still up with the baby. Anyone else hit this wall? Is this the 4 month regression everyone keeps mentioning? How long does this typically last?