Sudden aggressive behavior from 1 1/2 year old frilly

can any one advise me, ive got a frilly whos nearly 2 she has always been friendly and sits on my knee and on the curtains, has a bath etc but over the last few weeks she has been attacking me..... do they come into season???? shes gotten quite fat, do they lay unfertized eggs? shes not been with n e other fillies......