Blood sac in uterus in tri1

Went to doc for my scan at wk5, doc spotted a blood sac on top of the baby sac, baby sac is measuring ok for week 5 and blood sac is not active bleeding and im not bleeding it out externally. Doc say to observe another week and put my on hormones pill. Has anyone exp this before/ can offer adv? #adviceappreciated #firsttimemom