I had unprotected sex on 12 July but there was no ejaculation involved. My periods were due on 20th July but it didn't arrive on time. My periods are usually irregular. My had pineapple juice and thus my periods arrived on 4th August, the flow was less and lasted 3to 4 days. So this month my period was due on 4th September, but it is more than 19 days late. Is there any chance of pregnancy because of the earlier intercourse and what should I do now?