Is it possible to start getting fertile 1 day after my period finish?

Ovulation: If your periods are very regular, 28 days and you can feel when you ovulate you may be reliable to predict and it will typically fall 14 days later (+/- 2 days). If your cycles are irregular its very difficult to predict with certainty. An lh kit would be helpful if that is the case along with BBT charts. You will not be fertile a day since typically menses last 3-5 days, so day 6 is too early.