Thank you for your query.
From what history you give it is very non specific to pin point anything but i can discuss the possibilities. First supplementation of vitamin D is essential with proper exposure to sunlight .
Second evaluation for tuberculosis
or any kind of malignancy is required as you are having weight loss
and night sweats
I advise you to see a physician to get yourself completely evaluated .
Hope you are satisfied with the answer.
If you have any further queries feel free to ask.
Wish you good health.