I was prescribed hydrochlorothiazide 25mg about a week ago for hypertensions. Since I have been taking it, I have experienced extreme fatigue. For example, today I slept 14 hours and still feel tired. I've tried calling my doctor 3 times this week, but he has been unable to return my calls, and now will be closed until Monday. He did say that it would take some time for my body to get used to the medication, but this seems excessive. Is this a normal reaction?