I sex a week ago &started bleeding 3 days ago. Light/pink then dark red/clotting, now spotty/thick/brown. Could I be pregnant I shd be on my perid now?

Likely your period. The symptoms described are likely due to your period, especially if this is the time you are expecting your period. However, don't hesitate to see your gynecologist or family doctor if you are the least bit concerned about pregnancy.