I had a rabbit go through a nasty poisoning issue as well and I am glad Fraggles made it through ok. I hope she is still pooping normally? When my Tony had ivermectin (long story, I thought I was helping him, but he ended up having a genetic susceptibility to it that made it toxic to him), he was out of it for several days and at the vet with a similar treatment protocol. However, ivermectin has the opposite effect as theobromine--it is a depressant so they didn't need to give him sedation, he was already very low activity. Theobromine and caffeine (in chocolate) are stimulants, which is probably why her heart rate was elevated. For Tony, they could not get him to take the charcoal orally without fear of him getting it into his lungs, so he had a charcoal enema. He also wasn't eating while he was there, so combined with the charcoal, it took several days and gut motility drugs to help his GI get working normally again.
Again, so glad she is fine and that you got her to a good vet ASAP. I can personally tell you that is not expensive for toxic substance exposure vet bill. It is a good reminder that there are things we take for granted that can cause our bunnies harm.
Also a word to the wise--after my same Tony (who is a troublemaker, although the ivermectin wasn't accidental) ate a tiny bit of chocolate without getting sick, he started going nuts for it. He would try very hard to get it out of our hands, off the table, etc. Strangely enough, she may seek it out in the future--don't assume that this bad experience with it will register in her mind.