Yesterday is history, tomorrow is a mystery, but today is a gift. That's why they call it the 'present.'
Nothing happens actually. Hubby and I had sex 2 1/2 wks after our first child was born. Its different this time after #4 though. Its been 7 wks now and doesn't hurt as much. Just go based on how you feel. I think doctos just want to err on the side of caution and don't want you overextending yourself.