Didn't get a sticker for the transit w/o visa

Hi.im a Singaporean.Airline informed by that I didnt need visa due to visa free policy between Singapore/china.i arrived Pudong on 27th march suppose transit to seoul same day.due to changes in air.i was taken to a quarantine facility in Shanghai.ive been in QT since.i checked my passport and there is only stamp no sticker.how will that affect my exit.getting abit worried now with the visa situation