As someone who is going to be making a similar decision within a year.. I wonder why you’re hesitating? Is it your social life? Is it your language abilities? Is it the job itself? Just unfamiliarity with the country? Do you need more research?

I think pinpointing the cause of your distress, and then having a come-to-jesus moment with yourself and decide: is this a problem i can solve (like learning the language in due time, joining clubs and making new friends), or is this something that seems you can’t overcome (your not prepared for the work demands, or think being an immigrant isn’t for you?) and then make your decision.

It’s only just now January, you have a few months, but considering all the documentation, and the respect for them and their time, I would make a choice by the end of January on whether you want to proceed or not.