I Had My Periods From 1 September 2016 To 6

I had my periods from 1 September 2016 to 6 th September 2016 . I was supposed to get my periods on 7 or 8 October 2016 but didn't had. I did a home pregnancy test and it showed positive but 2 days later i had a test with my doctor and at that time it shows negative. My doctor advised me to take another home pregnancy test and also gave meprate . What should i do and how to make sure whether i am pregnant or not . Should i use meprate now or not . Please advise me.
Regards