what are the chances that I may get pregnant

There is a chance, probably not very high though.  It depends when you ovulate.  Normally, that would be between days 11-16 of your cycle.  Assuming a 6 day period, you had sex on day 8.  So, if you ovulate early there is a chance.

Plan B may be an option.  It is very effective within 72 hours.

Hope it helps.