I donated blood on Saturday and 45 mins later my heart was pounding, head hurting, sweating, dizzy and nauseous. I started to blackout but didn t. Went to dr on Monday, blood pressure 140/82, pulse 80, no eye or ear issues. Blood was taken on 6/4 and hemoglobin was 11.4. I now have pounding headache only when I standup or walk. When I lay down I m fine. Any ideas? PS. Not dizzy but I feel drunk when I m walking.