I've been into two jobs before that I did resigned effectively, the other one I have to render two weeks for the new hire to be taught by me.
The other one is good as soon as I have filed my resignation letter and it's the actual immediate effect.
@OP, it's okay. If you're no longer happy with the job and it is affecting your mental state, that's a good decision.
Thanks for your comments. Yes it was affecting my mental health. It impacted on my ability to get things done outside work. There are other jobs I can easily work at, so I'm looking forward to the future.
I've been there and done that. It is important to think of our mental wellness. If there are better jobs that don't have a lot of workload, pay lesser and you can easily work with happily, I'd choose that to do other things that I like.
But it is a bonus if that pays more or the same with the former.