Bleeding 4 weeks after c section

Hi all,

I had my baby just over 4 weeks ago and experienced very light bleeding or normal flow after my operation, when it got to weeks 2 to 3 there was little to no blood at all in my sanitary towels. My scar healed up pretty good so no issues there. However 2 days ago I started to bleed and thought, so my period has come? I’m exclusively breastfeeding and expressing to bottle feed so I didn’t expect a period so soon? I started the progesterone only pill a week ago too again you are not supposed to get a period? Also the flow was the heaviest I have experienced with a period and lots of clotting im just worried if I have done too much and it’s something to be concerned of, I’m changing my sanitary towels every 4 hours if that is an idea of blood loss. Today I’m also getting tenderness and pain across my tummy where I had the c section similar to after the operation (but not excruciating pain enough to go to a&e)

Have I done something wrong by taking the pill too soon I can’t help but feel worried and gps, health care worker and midwives will not answer the phones over weekends unfortunately.

Thanks in advance for any advice