Back pain and pink spotting, BFP today

Marissa • I have 2 girls, 12& 7 and my rainbow baby boys 5 and 2. 2 mc, 8/14 & 1/15.
I've had two miscarriages in the last year so I don't want to freak, but I guess that's my nature. I got my BFP today, called the doc for blood test tomorrow. I've had lower back pain on one side most of the day and now just saw pink spotting in discharge. Has anyone else had this?