Pap smear or birth control regularity?

Been on. Bc before.  Was Ortho tri cyclen for 3 months. Everything was normal during that time. Started gildess fe 1/20  Sunday the 7th . Had unprotected sex on the 10th. On the 14th (Sunday) had a Pap smear done . On the 16th(today) had brown blood. 
What could this mean?? Pregnant or regulating of the birth control. Been on this one at another time before this.