I'm guessing you mean has anyone gone back to work when their baby was this old? I've worked since ds was 6 weeks old, but have talked to others.
Anyway. Does he take a bottle at all? Have you tried? Has someone else tried with you out of the house?
A number of things might happen: he might take a bottle of ebm just fine (have you gotten a pump and given it a try? it can take a while to get used to pumping). If he will take a sippy cup, he could get liquid that way. I have heard of something called reverse cycling (there's another post on here about it). From what I understand, the baby might just not want to take a bottle and will nurse a lot when you are together. If he is getting solids, he will probably be just fine.
As for nursing to sleep, my son does the same thing. But when he is at daycare he goes to sleep for her. She usually rocks him to sleep, or just holds him, or sometimes he just goes to sleep where ever he is (carseat, playpen, etc.). They behave differently for other. When you find the right daycare it will work out.