Working fast food with POTS

I just got a job in fast food, after being out of work for almost a year now. My symptoms have been pretty bad but fluctuate and I have a lot of good day/weeks compared to just a few months ago but I still have bad days/weeks often. I really need this job not much of anywhere else is hiring and it's so hard to get a job. I've been dashing to keep money up but its just too much tear on the car and drains so much gas. I can't even bring myself to dash on the days I feel really bad even though its just sitting in a car the majority of the time and my boyfriend is normally the one driving. I worry that I'll have to quit quickly into the job but I really really need this. I asked for part time specifically because of medical problems but even 2-4 days a week sounds exhausting on some of the worse weeks. I obviously can't just go in whenever I feel fine and call out everyday I feel bad or I'm going to get fired from calling out so much. Is there anyway I can push through this? I know it probably wasn't the best idea to go for the job, but I really am in desperate need. Behind on car payment, credit card, and much more. It sucks and idk what to do. I've even considered applying for disability, but I don't really have time to wait to see if it gets approved or denied and then fight the possible denial.