Always tired for the past few days?

I've been drained, completely exhausted for about 5 or 6 days and every day I grow even more tired. I dont get it, I'm not sick or getting sick, I eat healthy and eat lots of vitamin B rich foods, take vitamin D every morning, I go for an hour or more bike ride at least once every day, II walk lots, and I get outside and get fresh air. It's not sun exhaustion either lol cause there hasn't been any sun for over a week, its just rain and clouds. And no, I'm not pregnant - thats what people keep telling me and its driving me nuts.Going to the doctors at this point in time isn't going to happen. It's a 3 to 4 week wait for the doctors appointment. Any ideas on why I'm so tired, or suggestions to try to fix it???? .