I started a new job just a few days ago, and I'm seriously considering quitting already. I had been looking forward to this position for months, but from Day 1, I felt like I wouldn't last more than three months here. It's a small team, and I found out that my predecessor left abruptly during a busy time, which has made me feel guilty about even thinking of leaving so soon. They had invested in my onboarding, including a drug test and fingerprinting, which adds to my hesitation. However, I can't shake the feeling that this job is not right for me. Within an hour of starting, I felt a deep sense of dread. I find myself panicking before work, unable to eat or sleep the night before. Even during my weekends, I'm preoccupied with thoughts about the job. I'm bracing myself for passive-aggressive comments from coworkers, and it's affecting my mental health. I thought it might just be nerves, but this feels different. I usually embrace new beginnings, but this experience has been overwhelming. I'm wondering if it's justified to pull the plug so soon. I'm open to any advice or thoughts on how to handle this situation.