Someone help please!!

This is not pregnancy related. Two days ago I found a bird egg just sitting in front my door, no mom in site. It has a crack in it and a little fluid coming out of it but I still made a nest and put it in the tree in my backyard since a lot birds nest there. Still yet it's abandoned, is the egg ok and what do I do? I've been checking on it ever since I'm so emotional I just need anything helpful.