I typed in 4 month old stopped sleeping and lo and behold I came across this gem and I found another article to confirm right here. After reading these two life saving articles all I could think was "Oh Thank GOD!" Not only do I now understand why baby boy hates everything, including me, I can also rest assured that it won't last. I also know what to look for and how to handle him when he whines incessantly, wakes up after fifteen minutes, and refuses to nurse for more than three sucks at a time without pulling away and looking at me like I'm torturing him. The kid is tired! And he doesn't know how to put himself to sleep anymore. Seriously. Despite the fact that last week he fell asleep while sitting upright and bouncing on your knee during a rousing game of Cranium with six of your closest friends, he's lost the ability to put himself to sleep. He's also lost the ability to stay asleep past that initial fifteen minute mark. Don't believe me? Go read those two articles!
After you check out the literature on 4 month old sleep regression, the affliction that has taken your little angel away from you, take a moment and hug your partner/support system, then go tell your baby that you love him and you know that he hasn't been replaced by aliens. Then rub his back until he goes back to sleep. Then go back to sleep yourself, right after you drink that bottle, er, glass of wine.