I have had bleeding for 3 weeks straight now, I am on the contraceptive pill Zelletta which used to be called Cerelle. I have been on this pill for months as I'm allergic to the combined and others and all has been fine up until about 3 weeks ago when I was bleeding watery blood then thicker and now it is nearly 3 weeks on and I am still bleeding scarlet blood regularly. What is the cause? I'm extremely concerned