Vitamin D definiciency certainly aggravates hair fall. Other common nutritional causes are Vit B12 deficiency and Ferritin deficiency. Kindly get this tested too. Also the patches of hair loss as you mention could be alopecia areta. Hair loss is a progressive problem and if not tackled in time tends to keep worsening over time. There are various causes of hair fall. Read my health feed for a better detailed understanding. https://fit.practo.com/#!/content/28405 After reading this I hope you will be convinced that a proper thorough examination of your scalp from a qualified dermatologist will be advisable for a fruitful outcome. Kindly get it evaluated first. You can drop by at my clinic for a proper thorough examination. Online consult would not be enough as Trichoscopic examination using a dermatoscope would also be needed and that cant be done online. Hope this was helpful.