I had an umprotective sex a week to my period. does that mean i can conceive?

Unlikely: If your periods are regular then it's very unlikely that your ovulation would be a wk prior to your next period.

Possible: Ovulation can occur Day 11 - 21 after the first day of the last menstrual period. This also depends whether you have a 28 day cycle. Normal cycles can range 28 - 32 days. Keep a calendar of your periods so you can determine when you are ovulating.