What Causes Cirrhosis Of Liver?

I went to hospital and was told that I had colitis and to follow up with gastro dr. They said I have cirrhosis of the liver. Liver function came back normal. No hepatitis. Colonoscopy and endoscopy were fine. They are going to do ultrasound in 6 months to find out where the cirrhosis is coming fro. I am confused since everything is normal.