Boobs not sore anymore?

I found out I was pregnant close to 7 weeks in.  I had had few symptoms up to that point.  But my boobs started feeling sore around that time.  Today is 9 weeks and I'm noticing that my boob soreness has gone down over the past few days. Has anyone else experienced this?  I have a Drs appt on Monday but thought I would ask.  Because I have spotted throughout this entire time I am extra worried about everything.  This past Monday we had an ultrasound and everything looked good, heartbeat of 171 bpm.  I'm just very scared!  Thanks for any experience!