Spotting during cycle


Hey all. I’m really confused and could do with some suggestions if possible.

I had my second round of <a href="">IUI</a> last month, which failed. Started my period (was heavy) and today is CD16. Just went to the toilet and when I wiped, I had blood. Not heavy, no clots, but I had to wipe a few times to get rid of it.

Any ideas? I can’t be pregnant, so it cannot be IB (same sex relationship and we haven’t done another <a href="">IUI</a> cycle this month).

Thanks in advance!