Sorry to hear that, and yes, you do get very attached to them very quickly.
My local vets run regular courses for people keeping stock and being new/inexperienced ( not saying you are, just what the courses are for ! ) owners, which covers basics like injections, lambing, foot issues, handling and so on. They showed a video clip of a CCTV camera set up in a lambing shed, which showed a heavily pregnant sheep laying down, just as another pregnant lady was doing the *crouch back end to wee* stance. The laying down sheep was very close, and as her back end hit the ground, she landed against the crouched back leg of the other one, and it broke the poor girls leg - completely freak accident, and just bad physics of weight and angles. They weren't even crowded in. Just wrong time wrong place, but still totally gutting for the owner. It is one of those things, but it doesn't make it any easier to deal with.