Thanks for everyone's kind words - it's good to know I have friends to talk with about this...
The reason Emma needs to be quiet and not more around too much after the shots is because once dead the heartworms will begin breaking down and be obsorbed by her body. If she is active, one of the worm pieces could break free and act like a clot causing Emma to have a heart attact or stroke.
So other than food and bathroom breaks or laying beside me Em will be in the crate for 6 weeks. The vet thinks this will give Emma the best results.
The only thing I can think of that should maybe have been a warning is sometimes Em snores or sounds a little moany when she is sleeping. But I thought that was because she needs to loose a little weight. The Vet says she is 3 lbs overweight - wants her to be 25 lbs at her size.