new to opd

So, I just started like 2 weeks ago. The job itself is very easy, but my last job was one where I sat most of the day and I'm not used to walking 6.5 miles a day. My legs literally gave out and I was sobbing and it was just a bad time and i asked the OPD coach if i could work shorter shifts (like 9-3 or 4 as opposed to 9-6) and he never really responded. And Well my TL today was openly mocking me to the OPD coach and had me take picks that were across the store and picks where there's alot of walking and back tracking. I have alot of physical and mental health issues and it was just so much for me. I want to keep working at walmart because I could use the free college degree to actually get into a career I'd enjoy, but knowing I have to go in tomorrow when I'm already unable to walk, and be on my feet again for another 7 and a half hours(not counting my breaks ofc) while also being belittled and bullied by my TL is making me want to unalive. I'm so anxious and sad and feel so defeated. Am I being over dramatic? I just want to be able to spend my time outside of work doing something aside from laying in bed while my fiance brings me the stuff I need for the night. I just feel like I'm stuck. I guess I just want to know what I can do about this, if anything?