It is distressing for sure! I mean you're confronting your fears so of course intense feelings will come up. If you arent ready though then dont do it because you will only be hurting yourself. Only start when you are 100% ready. My T made sure to ask me plenty of times before we started and once I said I'm ready we dove in, slowly through. At some parts I did stop my T from the exposure and even apologized but T reassured me that it was all in my control whether or not to move on to the next step!