I've never grieved before, am I grieving? or just upset?

About 2 weeks ago I had a miscarriage and after this happened, there were some complications, I had extra bleeding and my HCG levels were still way too high, when my stomach was felt by doctors, they said i still felt pregnant and I guess I was still holding onto anything that could mean I was still pregnant and I was gutted, but coping
My miscarriage was confirmed on wednesday and now it feels like i’m starting to grieve
I feel awful and I want my baby back so much!
I also don’t understand why i should grieve something that was never born?
It kind of feels like an imaginary relative has died, because no-one else is upset about it/undertands why I am upset?