Spotting out of nowhere

Mika • Married with 2 boys. Pregnant with #3 and #4!
I just went to the bathroom after getting home from work and when I wiped there was a little pink and brown. This is the third time I've had spotting the first two were after sex so I attributed it to that but this time all I did was come home from work do the dishes and there it was. Should I be worried? 7w2d