Starting a new job but what if...

I really do hope this query can be answered.
I have been offered a job and it is a very good opportunity, though very responsible.
I claim ESA and DLA, am in the WRAG group for ESA. Under normal circumstances, my ESA wouldn't become universal credit unti next year. However, due to the new benefit, I wouldn't be able to claim tax credits anymore but universal credit. And I am really worried about this. This job is part-time, looking at the calculations, I would just receive about £30 a week with UC, making me overall £78 a week better off working. I suffer from anxiety and mild agoraphobia, and other health issues and when I claimed tax credits before, if the job didn't work out (due to ill health in my case) then I could do a rapid recaim and go back to my orginal benefit of ESA (as long as it was within 12 weeks). But with UC, there appears to be all these sanctions (and hardly any available info regarding people who are disabled and working) and I don't know if you could just go back to the benefit that it would have been if you weren't working. This all feels an enormous risk for me, I am not at all sure if the job is right for me and I am terrified this change of circumstance making me go on to UC (when it wouldn't have been until next year normally if not working) will work out, and having to wait so long to be paid (as well as the fact my job would pay monthly in arrears too), this all feels completely overwhelming! If I have to leave the job, I am worried I wouldn be sanctioned and without money for months. Help!

Hi Gordon

Thank you.
Yes, full service UC area now where I live and the job is 21 hours.
What I am worried about is if I leave the job because it is too much for me, ill health, if I would then be sanctioned or of I would receive UC at a similar rate to what I am on now. And I suppose I would have to go through the whole process of being assessed again like I did for ESA? But it is if I leave my job through ill health, if I would be without money, etc.

Thank you Gordon.

Before, on tax credits, you could do that but I fear that now, if you did you could be sanctioned and have to go through the process of claiming again, as you say.
This is a great risk for people who suffer from ill health to move away from benefits.