Multiple babies

For you mommies that have more than one kid, how did you mentally handle having two or more babies. I want my daighter to have a sibling and i told my SO that if we can financially afford the first year without flaw that i want to try for our second around her first bday but i dont want to be mentally exhausted especially with a baby about to go into terrible twos before my other is even 6 months. Is it hard having kids that close in age or is it easier?