Spotting or period?? I can't tell!

I had my IUD inserted almost a month ago. I've had no spotting since 3 days after but now I've been bleeding/ spotting for 6 days. For the most part it's not enough to even use a tampon. It's mostly brown which I know is older blood so that makes me think I'm spotting but a couple times a day it's bright red so then I think that I'm on my period. Has anyone had this issue?