I have constant bright red heavy bleeding with a mirena (levonorgestrel) in place what could this be? I've been put on loestrin 24 to stop it and its not working

Could be the IUD. If you've had a recent iud insertion, it could be the actual iud itself causing the bleeding from a tear or laceration of the cervix or uterus. Give it some time and this should fix itself. If you've had the Mirena (levonorgestrel) for quite a while (over 3 months) and now have bleeding, see your gyn to evaluate for pregnancy, infection, or other causes of bleeding. You may need to have your iud removed.