My periods do that, there is often a lull in the middle. I have a heart-shaped uterus. I think one side finishes bleeding before the other side begins, but it might be just me thinking that. Do you know if you have a heart-shaped uterus? If you do, maybe that is why it happened like that.
I don't think so? I do have pcos and colitis though
My period does that every time I get it, I don't thinks it's a concern.