Level 51 character sudden death in Level 11 Freythorn Area

When I was playing in Act 1/Cruel realized that I missed Act 1 Freythorn Spirit bonus reward. I get back to Act 1 / Freythorn Area as soon as i completed the last Ritual and activate my Spirit Reward suddenly get one shooted. How can I get one shooted at Level 11 area with my Level 51 character played with 1k HP and 3.3k ES?