While I would also lean toward impaired iron absorption from the matcha if you are anemic without any other health problems, make no assumptions. Deficiencies of folic acid and B12 can cause anemia just as easily. Get an iron deficiency panel done (iron, ferritin, TIBC) to determine if your theory is correct before you take any action. If it is iron deficiency, I would be more inclined to just supplement with a little iron than to cut back on matcha.
I agree with everything Funk Odyssey said, and I would also add that if you're just going off of your hematocrit, that reading varies greatly with your level of hydration. I was a phlebotomist for several years at a plasma center and we had people get turned away all the time as "too anemic" because they had a glass or two of water that morning. Anyway, get more tests done before you decide to do anything.