It has happened to everyone at one time or another. You evaluate your options, work through the interview process and accept a new role, only to realise that your new position may not be all you hoped.
It could be something about the environment, the initial job description, the team, even the commute; once that feeling that you’re in the wrong place hits, it can be hard to shake.
The cause could be anxiety over your own abilities, or a curve in gelling with the team. Maybe your commute is more arduous than you anticipated.
In any case, if you hate your new job and aren’t sure what to do next, don’t panic; it’s not the end of the world. But it is vital that you think carefully before jumping ship at that early stage in your tenure.