How do I quit a job I just started?

I’ve been working there 2 days and I just can’t stand it. I feel like I should stay because the benefits are good for someone with my resume, but my mental health has been failing me for a while which is why I felt the need to leave my last job, and I don’t want to make myself do something I hate. They seem to like me at this new job, and it feels too rude to just disappear. I figured I would work my first week and quit on Friday, but I just don’t know what to do or say. Any advice is greatly appreciated.