I come on my period the 28th august but very light to my usual and it stopped the 30th when will i be fertial?

Depends on cycle day: Rule of thumb is that you Ovulate 2 weeks prior to your period. Keep a list of first day of period for several months. Then you can chart when it is expected and count back 2 weeks.

You will be: fertile 14 days before the first day of your next expected period. Sex any one of the 5 days leading to this day which is going to be the day that you are going to ovulate ends up with a pregnancy.