Does spotting only accrue when your pregnant? i had spotting a week before my period

No: Spotting is not in and of itself, correlated with pregnancy. Spotting is typically a sign of what we call, an 'unstable uterine lining'. Sometimes this is due to hormonal imbalances, or thryoid problems. If it's happening a lot then you may want to see a gynecologist to get checked out. If only this once, i wouldn't worry. If you had unprotected sex, check a home pregnancy test @ period due.