Some years ago I was sitting with Ralph (who taught accounting) and Jim (a management prof) lamenting my Spring student teaching evaluations. I had just completed two sections of our MBA OM course. Both were for full time students, with about 35 in each class. One section loved me (almost all perfect scores) and the other section didn’t seem to like me at all. I went through the written comments slowly and painfully, not knowing exactly what to change come Fall. Ralph and Jim had exactly the same problem. They were excellent and dedicated teachers, working hard to deliver a superior education. We finally took a vow to not obsess on written criticisms so much that it ruined our summers.
Were we over-reacting? Do we fixate on the few negative comments? With the forms now filled out online, half the class isn’t providing 
feedback and those that do are likely the ones with the axes to grind. And you know students run through them as quickly as possible and mark the task completed.
Here are some suggestions from Faculty Focus (May 30, 2018):
Step back. Read every positive comment three times and smile.
Look again later, but with objectivity. How many negative comments were there, versus no comments and positive ones? Delete the emotional language in the comment. Is there constructive feedback? Does the student have a point?
Decide what you’re going to do. (Doing nothing might be a perfectly appropriate response). Do you need more information? How might you get it? Are you considering making a change based on the feedback? How about some input before you do?
Talk to your own Ralph and Jim. Ask if they have any good ideas.
Talk to a few students. Students are good at clarifying what other students mean. They can venture some guesses as to how representative the comment might be.
Finally, recognize that you are not alone. Don’t in your wildest dreams imagine you are the only teacher who’s gotten a blistering comment.