Its a common condition after breast feeding for a long time. But don't worry it can be firmed using the procedure called Mastoplexy with or without implant. If your drooping is mild then implant alone will restore the sagging. But depending upon the breast size and the severity of sagging different method of mastoplexy may be performed. So your breast are small then i would suggest you to go for mastoplexy with augmentation. This might require 2-3 days stay on hospital. But yea consult your doctor personally before you plan to do so.