You waited 2 months before doing anything about it??? You're crazy
My ex shattered his left collarbone, quite similar to yours, surgery within 2wks of his crash gave him a 5.5" plate and 8 screws that he kept for a few months, then had surgery to remove them. He drank what I would call a "normal" amount of milk during his recovery, after each surgery, and is convinced that he saw a difference in his xrays when he slacked off on the calcium-intake.
Looks like you're doing good so far, I don't doubt that the doc wants to keep the plate in longer since there was a lag between the crash and the surgery - leave it for now, see about some calcium in some form if you're not a milk person (I'm not at all), and when it does come out, do your physical therapy.
Good luck!!