Im working for a big company in europe which basically sells shitty cheap stuff. The stores are constantly understaffed so they have to do lots of sending their employees around to cover shifts or "situations". "Situations" can be everything from having like having 30 pallets which need to be dismantled as they are brimful with packages filled with ther stuff we sell. Other "situations" were like when we had rats because our big deliverer couldnt keep his storehouses in check.
Atm we have the first "situation".
People are working overhours to get it fixed. Yesterday i had a 9 hour shift and today was my free day. My boss asked wheter I could help out today and I said no. Im workin there as a part time but most of the time they demand extra hours for you because the workload needs to be handled. 
Today my boss called and asked me to help out in another store. Sleepdrunkenly I agreed and after finding out i need like 2 hours to travel with by public means of transport for 5 hours work twice next week I went into the store and asked wheter I could switch with someone who has a car. 
I got screamed at by one coworker which was very unprofessional imo and my boss immediatly put on an annoyed face and commented how its life experience and he traveled far more for far less hours.
Then he told me I my workforce is like 50 percent max and Im just a "freeloader" who wants his hours and his healthcare quoting me from a few months ago. 
Then he told me he never even complained that I come to work "high" in the mornings ( which is not true. I have very bad sleeping habits and I use weed in the evening to relax) 
He argued my illness ( Morbus Crohn ) is something I always cry about and that I have 0 Teamspirit and every other coworker is better than me and showing more will to work. 
He told me if my illness is true im not able to work this job and should get a job in an office ( thats actually something i really would like tbh).
I asked him why hes not firing me if hes so disappointed in me and he argued that he cant simply find someone to fill the spot with. 
Afterwards we stopped discussing and I went into the store to grab a sheet of paper and wrote my termination. 
Im mentally and physically done and yet I feel bad for leaving as a lot of work is before them and my landlord is my friend and I need to find a new job quickly but apprently im a shit worker. My landlord told me he could understand me and that I shouldnt apologize to him but I dont wanna use my friendship status for extras. 
So AITA for quitting on the spot after being told what I was told only because I wanted to not travel far for little hours which would have been extra hours anyway. 
Im really unsure wheter im just a big baby and should man up or wheter I stood my ground and left b4 worse fallouts could have happened.
I really desire to into a clinic for mental health right now tbh.