You havent given any detail about your last menstrual period, if this period falls on actual expected period then it is highly unlikely it is a miscarriage
Heavy bleeding may cause big clots to form which may be misinterpreted as fetal tissue.
If you are really expecting pregnancy
you can always confirm with urine pregnancy test. You should do it as early as possible since it may become negative if the tissue expeled is really fetal tissue.
The symptoms are menstrual symptoms, and if it repeats you can take norethisterone
if you are not planing to get pregnant soon.