Miscarriage or not?

Hi all lady on glow, this is very strange and weird happen on me, on October 14 is day my period supposed to come, and I been taking pregnancy test since 12-14 and it came out negative, then on 14 in the evening my period is come, and it flow about 4 day, from 14-18, and then on 24 October I got light bleeding and spotting till 28 October so I feel nausea so I decide to take pregnancy test and it came out positive and call DR, do blood test and it came out positive too , hcg level is 45, I am not sure I am in the process of miscarriage or what ? But I am sure I got negative pregnancy test on 14, it flat negative, Anyone has similar symptoms like mine, or have early miscarriage symptoms like that? And I feel doubt if I have miscarriage my hcg level should go down than 45 cos it been two week away from my period day, please help or give some comment , if u know about it, thank Thank