I'm A Anglo Woman, 58 Yrs Old. The Hair On

I'm a Anglo woman, 58 yrs old. The hair on the right side of my head isn't growing. The left side is up to 2" to 3" longer. It's really strange. My hair was cut even the last time it was cut. Could this be because I stopped estrogen and progest replacement 9 mo. ago? My hair has always been very thick with lots of body.
Please help!