Implant

i just got put on the implant about a week ago and my boobs have been sore for the past few days which i expect to be normal; but i have pcos and i don’t normally have a period its been almost a year since my last one and she told me i’d have break through bleeding. When is this supposed to happen? i’ve read that it’s just like a normal period at first then gets lighter but i don’t have a “normal” HELP!!