Okay a bit of a hot take on my part, but if any of you have seen the Ice Age trilogy there was a theory about how everything was being played in reverse.
Ice Age; Collision Course: Manny desperately protects his family from an extinction level event, but Scrat our lovely prehistoric squirrel saves the day.
Ice Age; Continental Drift: Manny learns that being a father is hard and is just trying to be the best dad he can be, along with Diego getting a potential love interest. Sid is still being Sid.
Ice Age; The Meltdown: Manny meets Elie for the first time and manages to get Elie pregnant
Ice Age; Dawn of the Dinosaurs: Manny and Ellie have their child in the middle of a dangerous situation.
Ice Age: Manny loses his wife and daughter to humans who hunted them down intentionally aiming for him but killed his wife and daughter instead.
And at the beginning of Ice Age, Manny was intent of killing himself due to how all those around him either got killed or left him. Diego left so he could start a family with the female Tiger, Crash and Eddie left to mourn the loss of their sister and Niece. And the only one who managed to stay with Manny the longest, was Sid the first one who ever became his friend.
All before Sid decides to leave Manny due to how the mammoth had been pushing him away. Through his grief, Manny loses all those he loves and decides to end it all... only for Sid to come back and stop him from doing so saving the mammoth's life.