It's normal from any major surgery.
There's also something called ICU psychosis, that is pretty common to heart patients. Not because of the length of time in the ICU....but because of the seriousness of the surgery. My dad had it after bypass surgery and it happened after he was out of ICU, about a week after his surgery.
I had the ICU psychosis thing going on too - but since I knew what it was it was simple to control. It is all very strange.
I was coming out of all that emotional mess from my heart surgery until I had my abdominal aortic bypass on the 5th. I was right back to Square One.
Short of an autopsy or a brain transplant, that aortic bypass is the most traumatic surgery a body will endure. So I cry. Sometimes I cry about all the crying I do.