Measuring 3 Days Behind

I had my first ultrasound 4w6d and was told I was measuring 5w3d. Today I had my 7w2d ultrasound due to some spotting I’ve been having and I’m measuring 6w6d (3 days behind) baby has a heart rate of 130bpm. Has anyone else gone through something like this? Should I be worried?

My doctor ordered an ultrasound for next week. Just when I thought I could finally breathe, I feel like my air is taken away again.

This pregnancy has been absolutely draining everything from me. I just want to be okay and for my baby to be okay.