Hair Loss

Hiii... I got diagnosed with Crohn’s disease last year in May. Many doctors were on my case yet they didn’t know what I had until 5 days in the hospital. I had scars on my legs that were bleeding a lot. After my biopsy and a endoscopy, they found out I have Crohn’s disease but I didn’t have any stomach problems in the past. Anyways, it’s a year later, I have been getting remicade infusions for the past year. Lately, I have been noticing that my long thick hair is now long thin hair and I’m losing eyebrow hair. Doctors say it’s a vitamin problem but I don’t know what to think. Any idea y’all know what my problem is? Thanks