Unhappy and Concerned

I am very disappointed in the way the lecturer teaches and the way he speaks to us students in class and on a one-on-one call. It's frightening to even email him because of his negative feedback and criticism. I personally feel that if something is not done, I as student will suffer the consequences, in terms of my grades and my mental health. It is honestly very demotivating. This is the first time I'm experiencing such a problem with my lecturer.