The story I usually tell my friends who are just becoming parents is about this one night the first month, we were up constantly most nights. I don't remember on this particular night what I was up doing, it's not important, but what I do remember is being in the bathroom, sitting on the can, and looking down and seeing the floor move under my feet. Vividly. However, that memory sticks as a turning point for me - I didn't have a whole lot of self doubt about doing a good job as a dad after getting through sleep deprivation induced hallucinations!