Hey ladies, looking for some advice!

I'm supposed to be 10 weeks pregnant based on the first day of my last period. When I went for my first ultrasound they said it was measuring really small. If I calculate my dates from when I believe I would have ovulated and conceived I would be between 6-7 weeks. Which I saw to ER doctors yesterday who both agreed. Been having some brown spotting since they did the internal ultrasound. Waiting on blood work again this week to see if my levels are still increasing and I'm just only 6 weeks or I'm miscarrying.

Has anyone else experienced this? Good or bad I'd like to hear it. Its heartwrenching going in expecting to see a growing babe on the ultrasound and not having that. The waiting game is hard and after trying for so long to finally have that positive all I want is a healthy baby!