Sounds a lot to be dealing with.
Can you ask for an extension on your essay, or on your Math assignments? I am sure your dr would be willing to write and explain that you could do with a bit of slack right now.
Be gentle with yourself - sounds like you need to take a break and regain perspective and focus. Sometimes it helps me to list what I need to do and then prioritise. I even make the comment to others sometimes, "that job is no. 342 on my list. Which others do you suggest I drop to move it higher?"