Good idea re antibodies! It's the only why they can get any.
You sure can relactate, as others have said, the key is to feed, feed, feed. Are you able to take a little time out and just do that to reestablish supply? the ABA and/or an LC would be able to offer you advice also. Barb also has experience with this too.
Good luck!

PS, hope they're all well again soon