Hello Dr,my Periods Are Delayed By 124 Days .I Did

Hello dr,my periods are delayed by 124 days .I did pregnancy test 2 times n both were negative. Doctor has suggested me deviry-10mg, which i consumed from 7th of this month. Last night i saw a little blood and thought my periods are back,but in the morning there was no blood.i am having a terrible back ache which i used to get during my cycle. Please do help.