Weird period

Kiwi • Trying for our rainbow after losing our twins in December 2016, conceived by iui. :)
So I'm not normally regular. I had a ovarian drilling last November and since January I have had a 28 day cycle each month. 
This month I was two days late and I just put it down to my body reverting into its old tricks. 
On day three past expected period I took a test and was negative, later that day I spotted brown blood, very little amount. This lasted three days. 
Well today , 3 days past weird period I am now bleeding like my normal period with cramps and all.
It's so weird! Has anyone else had this before. Was I technically a week late ? 
And what was the three day brown blood about ? 
Thanks in advance