I realize you "need" the job but it sounds like you faked your way through the process and your employer will expect you do be in better shape than you really are. This is not a good position to have put either of you in.
Be thankful you have insurance and a landlord who would let you have months of 'free rent' that you can pay back. Many have neither.
If the employer,part time, full time, temp whatever detects a back problem(and obviously a serious one ) not disclosed the new hire is history due to deception which no amount of prayers will remedy as this leaves the employer open to all kinds of legal BS.
That has the potential to really screw up chances for any thing else farther down the road especially if this is a small community which was indicated by the response back to my initial posting.
I faked my way through a DOT physical one time,hiding a knee problem. I later re-injured my knee on the job and was given the chance to resign vs get fired for not disclosing and fraud.
I took the offer as they were aware that what I said happened on the job could not cause the amount of damage seen by the MRI on my knee. The deception and aggravation and lying were not worth it.
I learned a good lesson and I was relieved when the ordeal was over as I no longer had to live a lie. The next job I applied for I disclosed the knee and they said thats OK we like your other qualifications and I was there for 4 years and after that again found something better.
I can understand fully the urgency to find employment but living a lie will only cause grief later on.
My surgeon expected me to be in better condition for work than I am. I didn’t fake my way through, I just didn’t mentino that I would be having surgery because my doctor didn’t think it would interfere with my ability to do the job.