Bleeding

I have 3 active pills left in my 1.5/30 Microgestin pack of pills.  Last evening, I started bleeding, nothing too heavy, but enough.  I have the normal monthly cramping that usually accompanies the week of brown inactive pills in my pack.  A week ago today I had ankle surgery with no complications. 

 Could the bleeding be in response to stress within the body?

Should I continue my pack and start my new pack the same as if no bleeding has occurred?