My period date is 15th March..

I got brown spots on 11th morning (when I wiped after peeing)..after that the periods didn't start...

Yesterday on 13,th March morning I got few spots again when I wiped after peeing... today it's 14th March period flow hasn't started yet ... having leg cramps,,, feeling very sick ,, having a sensation in breast...I did the pregnancy test..it is negative...can anyone suggest what to do... because it never ever happened to me before... whenever I found spots after peeing, in just a few hours my periods used to start.... really very confusing