7weeks spotting and Ultrasound

Yesterday I went in for my first OB appt since my BFP. After weight and BP were taken I had to give a urine sample. I realized in the bathroom that I was spotting. Midwife immediately found a doc to do an ultrasound. Of course I'm a mess with worry but my worry was quickly washed away when I heard the doc say "you have a baby with a heartbeat!" This tiny Jelly Belly is measuring a little small at 6w2d (I was exactly 7w0d) but doc said that was still within normal range. I have a follow up ultrasound in 2 weeks. Doc said the the blood was old and probably leftover implantation bleeding. Also was told chance of miscarriage goes way down which I know can happen no matter what the percentage is but I appreciated the words of comfort.