Help me

Sarita • Mommy of 1 and will be ttc in a few for our rainbow 🌈 baby.

I’m sooo anxious to know how far along I am. Can anyone help? Has anyone had a miscarriage and got right right pregnant without having a period. I had a miscarriage and my period didn’t come, all I got was a positive pregnancy test. Or does anyone know how I would calculate it? Or do I have to wait until an ultrasound? 🤦🏾‍♂️