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The altered discharge suggests possibility of hormonal disturbance due to sudden periods in between and starting of new pack. If the discharge continues for more than 2 weeks time, then get it evaluated by your gynecologist to make sure there are no other underlying problems. Continue to take the present pack of pills regularly without missing them in between, and if you do miss them use additional protection (condoms/spermicide).
If you are worried about pregnancy and 72 hours are not yet up since your last unprotected intercourse, then discuss with your gynecologist and consider taking emergency contraception.
Take care.