Re: cow's milk...
As the PP's have said, it's probably better to give formula for the next month and a half and then switch to cow's milk. Formula is no match for mama's milk, but it definitely beats cow's milk in terms of offering the right mix of sugars, proteins, fatty acids, etc.
If your preggo breasts can still bear to combo-feed, your LO will still be getting lots of immunities and other good things from your milk, and you'll be getting a break.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"