Migrating to UC

Hello

I just received a 'You are Migrating to UC' letter in the post.

To say these letters from the DWP cause me great stress is an understatement, i am wondering has anybody been through this procedure before? 

I am in the support group of ESA at the minute and i am worried that there is not the same category in the UC system

Did you have to be reassessed for your condition/Autism?

Does anybody know of any services aside from CAB that can help?

Thanks