Occasional passage of blood or small blood clots is mostly common during pregnancy if you had physical exertion or lifted any heavy weight or it could be due to any other unknown reason. I would suggest you have complete bed rest today observe your sumptoms if you come across any heavy bleeding or pain i would suggest to go to nearest hospital and get checked up if this bleeding was just one of the case there is probably nothing to worry as today gynaecologist is closed I will say visit him or her tomorow and just check if everything with baby is ok.