I wound up in the hospital a few years back. Started with getting dizzy when at the Y and doing exercises on the mat. Then it progressed to shortness of breath, then it progressed to chest pain and I thought I was going to have a heart attack so drove myself to the ER and they did blood work and said we are going to admit you. I asked why. He said your blood is down to 5.5. So had a blood transfusion, and two bags of iron. Evidently I was bleeding internally, but it was such a slow bleed I never saw blood. I do have AVM's and that was what was bleeding. Now I can't take aspirin, nor my Celebrex for Arthritis so live in pain with arthritis. I found out that I had AVM's and asked the doctor about them, and all he said was they could bleed but didn't mention I might not see blood. So with my blood being 5.5 and they want you in the teens the nurse at the ER said I'm surprised you are walking. I remember asking my hubby if I looked pale and he said NO! After finding out, now I can't trust how I look anymore. I just started having some issues and thought it could be the blood again but it isn't.