I had a sex with my boyfriend on 7th aug and on 16th aug I had my regular periods. But after that till date(1st oct) I didn't had my period, am I pregnant. I always have irregular periods.

Pregnancy is impossible to determine via the internet. The only way to know is to take a pregnancy test.

Having irregular periods makes it difficult to get pregnant I used to have irregular periods because I was over weight "not saying you are" my doctor put me on birth control and glucophage to regulate my periods and to try and help me conceive, good luck

Glucophage is prescribed to "control" Type 2 Diabetes. You were given a prescription to regulate your periods?