Am I in hot water?

I’ve been working at a new job for the past year and absolutely hate it. When I took on the role I envisioned something entirely different than what it actually is. It is a new role at the company so there was no blueprint or official “training” on how to do the job. I anticipated I could make it my own and figure things out along the way. My previous company was going through mass layoffs so I really wanted to secure a job at the time. I thought things would be better by now, but they just aren’t. I recently saw an internal job posting that I was interested in applying for and went for it. However, I didn’t advise my boss before applying only after I applied for the position. Felt like a rookie mistake and now I feel the awkward tension of them wondering if I’m happy here or not. I ended up withdrawing from the position as I just didn’t feel like I would get it and the encouragement and support wasn’t really there. I’ve apologized to my manager for the mistake of not telling them before hand, but now I just feel like I am in the hot spot and that they are going to watch me like a hawk. We had a conversation about why I applied and I was somewhat honest, but couldn’t completely tell them I hate the job. Everyone tells me to stick it out since the job market sucks right now and I’m a teleworker. Mentally I feel like I’m checked out and afraid I might eventually be fired for this. Anyone else experience such a thing? How can I fix this or try to make my experience better.