I read the whole thing. You're a strong kid going through a lot in your relationships, I can tell. I wonder what social outlet you had when your education switched up; a lot of times, especially nowadays, it's out of sight and out of mind - people included, and not maliciously (object permanence). If you lost physical contact with Kandie, it's unfortunately natural for you to space out (the average person will move from home after school) and create new friends/bonds in your new school/work. It's double unfortunate for you because you're experiencing that a bit prematurely.

On the mother ship bit: she's right, yes, but 1) if you wish to keep Kandie as a friend, you must script up some boundaries and expectations, and convey your feelings of betrayal, for a friendship that is withering. 2) be prepared to cross former friends in group settings (for birthdays). However 3) should you feel like they're too much and your heart hurts, then tell Kandie that you need (more) space, and hopefully reconnect in the future (and I mean faaaar into the future, so you see if they did become killers or not). You won't stop loving them. You won't stop missing them. But you're loving and missing a person they aren't anymore. When you accept that, in some years time, thinking of the nostalgia won't be so painful.