Miscarry and still pregnant?

Hi,

At 3rd week of pregnancy I had my period. It was no different than a regular period, slightly back pain tho.

After that I went to the doctor and they said my blood hcg hormones were very low and that I probably miscarried it.

I would’ve been 5 weeks now. I took a test yesterday and it’s showing a slight positive.

Is it possible to still be pregnant and maybe carry a twin and lose one?

I feel very much pregnant physically and in my heart..