How do i quit my job at walmart?

I started working at walmart about a month ago., two days ago i had a seizure 2 hours before i had to end my shift. I hadn’t had one in a long time and it freaked me out, honestly. My husband wants me to quit so that i can go to the doc and sort myself out before i go back to work. Id go back to being a housewife to my dismay, but i also want to know why i got the seizure again, and i need to fix the problem. (No im not on meds since itd been a while since i had one). I also dont want to quit cuz i feel like im letting my manager down. When i quit idk how ill ever step into that walmart again since i feel ashamed for quitting. How do i quit?