Well I have an online exam tomorrow in one of my classes and I have an online class where I basically did nothing in that class this week and the assignments are due tomorrow before midnight. That on top of work stuff and one more thing in another class that's also due tomorrow.
My advice would just be to rank order the things you need to get done in order of importance, probably going to be that exam since it will be worth the most % of your grade compared to an assignment, and to tackle each thing on it's own. So for example, study for your exam without thinking of anything else, push the other assignments out of your head (since thinking about them while studying won't help).
The worst thing to do is list out everything you have to do. You have to compartmentalize this stuff and do it one at a time
Also, if you can't get everything turned in before the due date, it's going to be alright.
I would reach out and talk to your teachers and genuinely tell them that you're struggling, that you want to do the work, that stuff piled up, and that you could get it done if you got an extension. It's gonna be okay