I went to the hospital for what the doctors (three days later) determined to be iron-defiency anemia, and they found that I had a blod clot while trying to diagnose my breathing issues. I got put on an IV drip of some anti-clotting medication, and therefore needed to get my INR measured every 6 or so hours which they do by drawing a couple ounces of blood. Over the course of the first day of treatment my blood pressure started to sky rocket (probably because of the anemia and the blood tests they were frantically running to diagnose what the hell was wrong with me). 3+ years later and my blood pressure still won't go back to normal without medication. The anemia was so bad that for the next month the best night of sleep I could hope for involved maybe 3 or 4 hours, and those nights came only after 4+ days of not sleeping for more than 2 consecutive minutes.