The plot thickens!

After chatting with my sister this morning, it seems this whole friend situation is a little more complicated than originally thought. First of all, my sister did receive those emails Lily claimed I sent to her by mistake - how would that happen? It's not that I sent them to Lil instead of Heathy, and Heathy, who saved all the emails, said there's no cc: or anything like that, so how could I have 'mistakenly' sent them to both of them? And get this! That comment Lily made about my saying her mother hadn't taught her manners - HEATHY wrote that to ME! So what the fuck is going on here? Was she somehow reading my mail?
As Heathy said to me this morning, it's all a moot point, really, but still - I wanna know!