Random Pink Spotting

Amanda • I'm 27, I have three sons they are in age range from 7-3 and I'm pregnant with my fifth pregnancy.
It started after I found out I was pregnant after sex, then left, then came back after walking a mile yesterday and again tonight after sex... have any of you moms experienced that, I'm also in the process of moving from Mass to Maine and am trying to find an obgyn place to be seen (haven't been seen yet) I'm currently in Livermore falls area... thanks ladies 
oh should I be worried ... there is no cramping too so it's odd very odd