Pregnancy is nerve racking

I am around 9 weeks pregnant. I have a dating ultrasound set for this coming Wednesday. I had pink spotting yesterday and freaked right out (I had a miscarriage almost exactly a year ago) I went to the ER and after about 5 hours of waiting get an ultrasound ... Baby was in there with its little heart beating at 179/minute. I have never felt so relieved at seeing that little flicker on the screen. They sent me home and told me to try not to worry. I am still spotting off and on today but it is brown and barely there so I am hoping everything is ok. But my stress levels are out of control ahhhh.