Are you male or female?
Do you live in a four season region?
Its the winter, you're spending more time indoors in climate controlled spaces, so it adds up that your scalp and hair are drier than in the warmer months.
Two things I picked up on that I could have used when I had a full head of hair.
Beard soap works well as a shampoo for me, and Vitamin E oil works well as moisturizer.