You should read http://www.vitamindcouncil.org/about-vitamin-d/vitamin-d-and-other-vitamins-and-minerals/. Your Vitamin D level is so low, I would take “no chances” and get some calcium (500-800mg) and magnesium supplements. You are in the Osteomalacia range.
Is the 50,000iu Vitamin D2 or D3? This is very important because D3 is better for humans to take then D2. If it is D2 you can substitute D3 either 50,000 iu once a week or even better for you is to take it daily which is about 8000iu a day. (Your level is so low, you could take 10,000iu a day.) If you weigh more than 150lbs, you may even have to take more.
I would hope you feel better within a month or two but cannot guarantee. If you have more questions, just ask!