First period with IUD

So I got my IUD December 27th, 2017, on the last day of my period. I've had the typical spotting here and there. It has only been a little.

So Sunday January 21st, 2018 was when my next period was supposed to start. It started but the blood is bright with very small clots and lining. But the blood part is bright pink/red. The bleeding isn't heavy. I have Endometriosis so my periods are HEAVY and long. So far my period has been light and the cramping has been moderate. The only thing the concerns me is the bright red blood. Has anyone experienced this?