How much time should I give a new job to judge if it’s a good fit or not?

I’ve been in a new job for a few weeks after being hired through a recruiter. It’s been a very high stress time for my family as we had a family member pass away around the time I started, so I’ve been “working through the grief” and I know my performance isn’t at the level it should be. <br><br>I am feeling completely frustrated and defeated in my role. It doesn’t feel like the right fit at all and I’m wondering if I’m just feeling this way bc of my headspace. Is 3-4 wks enough time to judge if a job is right for you or do I need to give it more time?<br><br>TLDR: How much time should I give a job before I decide if it’s a good fit or not?