NEED HELP!?

Unfortunately I had a miscarriage on Tuesday 16th where the doctor said my cervix was still closed even though i had passed the sac! He didnt give me a scan even though i was 8 weeks and just told me to take a test every week until negative but now i still feel very pregnant! I know i will for a while but something isnt right! My partner has a strong hold of twins in his family! And i always said from the beginning i think its twins! I seen my doctor on friday and she gave me the depo shot and booked me a scan? Shouldnt she have gave me a scan then a depo? And is it possible i could still be infact pregnant because bleeding stopped cervix closed? Im not getting my hopes up but im confused as to why my cervix isnt open?!