Did anyone experience co parenting anxiety?

This is long My son's father keeps asking me to pick up my son from school on his days on and off. Last year I helped him out by staying with my son full time for 6 weeks straight, in March I had to pick up my son on most of his days but tye dad would pick him up later often around 8pm to 9pm. Early in February he said he changed job for more money and asked to pick my son from the after school club because I have a 9-5 job. I said it was his responsibility to make sure he's got the childcare arrangements to support the job schedule. Yet I ended up picking my son up the whole month of March on his days. Guess what he asked me again to do the same for April and I said no. March was tough on me as my routine was messed up. I always gets stressed on drop offs because of the separation. When my son is not here it's hard to go back to my routine. That hard on fixed schedule but it's even harder when you don't know what your week will look like from one to the next. I'd like to know how do you cope with you routine always changing with the other co-parent. Sorry for the rent...