A lot of people that find their way here, have extremely low levels.
You are the second person recently who is “relatively speaking” not too bad. By that I mean you are no where near the optimal goal of 50ng/ml and you do have symptoms of low Vitamin D BUT taking 5000iu for 8 weeks just may be enough to correct all this. (Let me know, though, if you weigh a lot more than 150lbs.)
Having said that, some people give themselves a boost in the early weeks. So you could take 10,000iu everyday for one or two weeks and then go to 5000iu a day.
If you have any questions, just ask!
Whatever you do make sure if you want to retest that you stay on any given amount for a total of 8 weeks. This is so you can determine what level you get to on any given amount of Vitamin D.
If you feel fine after the 8 weeks, then keep taking 5000iu. IF you do not feel well, then I would try and retest to see what levels you have. I would also come back and tell me if you are not completely better. Do not correlate levels with how you feel!