Progesta medication

Hi mommies. Went for my 7 week scan today. Doctor saw 2 sacs. 1 sac is empty and the other sac had embryo and could hear heartbeat. Doc Said most probably initially it started out as twins but the 1 egg did not fertilise that’s why there’s 2 sacs. I also do not have twins gènes in m’y family Line. Prescribed me progesta for 1 month, vaginal insert to assist in case there might be light spotting from the empty sac trying to release itself. Doc Said thé medicine is to help with this. Next scan is 10 weeks However I feel abit doubtful to have this med. as i was thinking it might affect my healthy embryo and sac? Did anyone have the same experience before or if thé specific medicine helps with what doc said? #firstmom