Bish
Forgive me but it's not clear from your post whether you have received an award or not?
PIP legally requires a claimant to have suffered from the limitations that result in an award for at least three months, if your conditions are new then it would be correct that this period would not be included.
I'm afraid, without a clearer understanding of why you have/have not been awarded and what you have requested the MR over it's not possible to offer more advice at this time.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems