Claiming JSA and potential sanction

I wondered if anyone was in a position to advise on my situation. I have resigned my job to start a new one on Monday and got a call this morning to say the job had been cancelled. Therefore I will be jobless and need to claim JSA - without it I will have zero income and will pretty soon end up on the streets as I have no savings. I understand that people can be sanctioned for just resigning a job. Can anyone advise whether this is likely to be the situation I will face? This is adversely affecting my mental health issues, which I have managed to get on top of in the last few months.

Thanks in advance

NNOP