leftover milk :(

lbarrera86

What is the rule about reusing leftover milk? I am so stupid...I should've followed my gut instinct. I thawed a bag of milk which contained 4 ounces. My DS3 is 2.5 months and usually finishes 2-3 ounces, occasionally 4, and one time finished 5 ounces. I was going to make 2 - 2 oz bottles but for some reason, I thought "hey, maybe he'll drink 4 today." Well he finished 3. It makes me sad when he doesn't finish the milk because BM is just so precious..plus it takes me a long time to pump and get an adequate amount. 

 So is it reusable? If so, how long can I wait until I toss it? Also, do I put leftover milk in the fridge and reheat before I give it to him again? He only takes really warm milk.