I feel incredibly tired and and dizzy all day, what could be wrong with me? Please read the details for more, well, details.
I eat well and sleep for 7-9 hours each night, and exercise regularly, but lately (the past week) I've been feeling overly tired and am having trouble standing or walking for extended periods of time because of dizziness. I also get dizzy whenever I stand up from a chair or sit down, and sometimes the dizziness hits me even when I'm doing nothing. This has never happened to me before, so what could it be?