Should I quit a job after 1 week?

I’d posted previously about reservations I had for this contract. It’s a maternity leave cover (12 Months) which I normally don’t accept though there weren’t a lot of offers coming through.
So I’ve done one week and the commute is 4.5hrs per day 3 days per week then WFH 2 days. The onboarding process has been rushed. Left alone a lot of the time and the plan the manager made for me keeps changing. I haven’t found the people overly interested in making effort to get to know me (not that I expect the red carpet haha) though a bit of interest doesn’t go astray. On top of this, the job is huge. Here’s the best bit.. the handover is being done by the pregnant woman who is way past due! She hasn’t written anything out and has come in for a few hours to show me a few things and apparently that’s that.

I feel pretty unmotivated and not loving the morale overall plus I feel like I’ve been handed the keys with no instruction.

I’m tempted to send an email and say it’s not working. On one hand, I don’t want to let them down and on the other, I really don’t want to return tomorrow.

Any advise? Thanks!