I am an undergraduate student who has been conducting research with a professor for the past year. Unfortunately, I have been feeling defeated lately because the professor I am working with is extremely callous and patronizing. Every time I interact with them, I walk away feeling like the dumbest person alive. Although we initially got along for a couple of months, things changed after I made a minor mistake. Since then, this professor has been really hard on me. They even threatened to write me a negative recommendation letter for grad school as a result of my mistake. Whenever I ask them questions, they respond in a condescending manner, as if I should already know the answer.
To put it simply, it feels like the professor has thrown me into deep water and refuses to help me stay afloat. I am really tired of being treated this way. Even though I am trying my best to do well, things are starting to feel really heavy. I dread interacting with this professor and sometimes feel like quitting. I don't know why I am writing this, but I guess I am asking for suggestions on how to proceed. Should I confront the professor in a mature manner? Should I tell another professor or someone in a position of power at the school? I am at a loss.