Could I be pregnant?

Patient: I had unprotected sex but I am on birth control. I am in the 2nd week of my cycle, I will start my period on the 14th. However the past few days I have constantly felt nauseous, experienced slight cramping, slightly irritable, and have a brown discharge. Could I be pregnant or could these be signs of other things?

Symptoms: Nausea, cramping, brown discharge