Thin hair products?

Hi!

My husbands mom cut my hair the other day and said my hair felt a lot thinner. I have such a dry and itchy scalp (usually to the top back of my head). I feel like I’m definitely losing hair every time I brush my fingers through I have about 4-5 strands come out. I’ve definitely been stressing lately and my mother in law told me to take hair skin and nail vitamins. So I just started taking those and ordered a silk pillow case. I usually wash 2-3 times a week, air dry my hair, and rarely put heat on it. Any products that work wonders for dry, thin straight hair?

Thank you!!