I had a blood transfusion last week thursday and ever since i got out the hospital i've been swollen with a bad headache. ?

I see: Mild transfusion reactions are treated with diphenhydramine (Benadryl), however it would be unusual to be experiencing such a response from a transfusion almost a week afterwards. In this situation, I would more suspect whatever underlying problem caused you to require a blood transfusion, which usually must be very severe. Would speak with your doc who knows your unique situation.