Calling in sick 2 weeks into a job

Thanks everyone, I do need to put my health first, I don't know what I was thinking when I agreed to 16 hours at once.

I would call in sick and start looking for another job frankly.

They won’t give you a second thought if you end up unable to continue working, only you can give yourself the care you need to continue working (for minimum wage too). I know it’s a real dilemma but you have to be firm and put your own health first. If you make a mistake from being over-worked you know how you will be treated from the lack of consideration given already.

Your need to look after yourself. My instinct is to say, "Leave - now!" although I realise that is probably a financial impossibility. But you need rest and proper sleep so tell them you won't be in tonight. You'll be no use to the residents or colleagues if you're so exhausted and unwell.
Make it clear to the management that, in future, you will not be agreeing to work extra shifts or 16 hour stints and will work only your contracted hours.
Night work plays havoc with the body's systems and can lead to long term health problems in the future so, for your own and your family's sake, your responsibility is to yourself.
Tell them you won't be in tonight and go and get some sleep.

Colleague said she had never seen me looking so bad and that the colour had drained from me