Blood in my urine

Hello I am a 29 year old male and I have recently noticed that I have a lot of blood in my urine. I have seen my family doctor as well as gone into the closest hospital when it first started. They did an ultrasound & a cystoctopy and both came back normal. But yet the blood has continued they have checked for a urinary track infection and I do not have that. However I believe I have too much protein in my urine because it is more foamy & bubbly then normal. I have had a kidney stone in the past and it does not feel like that. At first when the blood started I had no pain at all bit as time goes on I am starting to have more and more pain in my lower back right above my hips. The blood tends to be more present when I am a little dehisrated. Now just to make things more difficult I am on a blood thinner due to a rare clotting disorder. I have been checking my INR and it has been in the proper ranges it needs to be in. So I am now starting to completely freak out in that I do not know what is wrong with me.

Bstretch