Temporary crazy schedule, toddler flipping out
I'm so sorry you're having such a struggle with your little one and I wish I had seen your post earlier. I'm sorry it was missed and I hope things are better now.
It sounds like he just feels stressed by the sudden change of your extended absence and a new sitter. I suspect all he needs is some calm and loving undivided attention from you to show him all is well. I know that is not always possible so I hope you can work though it somehow and come up on the bright side of content little boy and mama.
I've also been coming out of a really stressful, busy time at work (tho not 24-hour shifts!) & I definitely see the effects on my son. AND I also find I have the least amount of patience when I need it the most. You need to recover just as much as he does, so I hope you're able to forgive yourself if you are not the parent you want to be.
BTW, at 2, I noticed that even getting back to the work week after a weekend would stress out my DS, so this is all normal stuff. I hope you've been able to find so time to recoup together!