I Had Unprotected Sex About 2 Weeks Before My Period

I had unprotected sex about 2 weeks before my period was due. About a week later I started spotting. At first I thought it was just my period coming early. But it has been anywhere from light brown, dark brown, or light red. This has been going on about 5 days and I have cramping like it's my period, but I've only been spotting. Could I be pregnant? I've had trouble conceiving for a very long time.