I had sex on 27th August .After 27th august i had not done any sex till now.

Taken contraceptive pills (SAHELI) Centchroman 30 mg from 6th august to 5th october 2013 After that i stopped taking contraceptive pills . I had normal periods on 20th September . But im worried as October periods are delayed by 7 days . What should i do?Am i pregnant?