The 4-month sleep regression is REAL and I have proof

Our son went from sleeping pretty solid (8pm-5am with one feeding) to waking up like 6 times a night. Started around 3.5 months and is now at 4.5 months and somehow worse. I read all the stuff online about regression and developmental leaps but knowing WHY doesn't make 4am less painful.

Wife and I are barely functioning. We've been snapping at each other over stupid stuff. Took him to pediatrician to rule out reflux or other issues - he's fine, just a jerk. JK but also... when does this end??? Anyone past this and can tell me there's light at the end?