Not sure what to do now 🤔

So yesterday when I called into work I called and said I had a UTI and couldn't make it for my over night shift. My supervisor told me to bring in a doctors note and I'm fucked bc I have work tomorrow and didn't even go to the doctor. Anyone have any advise on what I should do? I was thinking about maybe just telling him it turned out to be a fever instead of a UTI so I didn't go to the doctors since sometimes you can get fever like symptoms while having a UTI? What do y'all think? (To be clear I didn't really feel sick or have a UTI I just really needed a day off)