6 weeks Pregnant and Spotting... Help!

Hi Ladies,

I'm six weeks pregnant (3 days short of 7 weeks) and yesterday morning I noticed a bit of blood when I wiped.There was nothing on my underwear and it has not continued since. On Monday, I had an ultrasound and both baby and heartbeat looked good. I called my doctor and he had me stop by for blood work (results ready next week) and scheduled me for an ultrasound on Monday. Has this happened to anyone else? I'm so worried about miscarrying and praying for a sticky baby. I'm trying my best to remain calm vut I am freaking out.