E.I.
draw the line. you say she follows you when you walk away? what if you prevent the following?
my son would throw a tantrum and i knew he was just tired of playing with the other kid (i have in home child care) so i literally would send him to his room, and shut the door. he maybe would whine a little at the door, but then he would play alone in his room for a while, and before too long, he would knock on his door and be recovered :P
so, i guess try it. just shut a door; put up a gate, whatever, so the following doesnt happen
good luck... the only way to get rid of an undesireable habit is to fulfill the needs, then ignore tantrums COMPLETELY (at least at home) any attentino, even negative attention, is still attention.