It sounds like you're having a hard time with everything, I am really sorry to hear that.
Try this: Instead of trying to complete the whole piece as one, try just completing one section at a time and worry about getting through this hour and this alone, forget about everything else.
For the time managment, I am not too sure, that's something you're going to have to work out by yourself. Try writing everything down and seeing where you have time slots to work on your assignment, I suggest taking a 15 break every hour or so.
I am not going to try and pretend that I am going to understand what you're going through because I have no idea what you are going through but if you want professional help, I can suggest headspace. Headspace do a webchat service where between 9 am and 1 am you can talk to a health professional about things that are troubling you. You can simply register and provide very basic information about yourself (more info you provided, the easily it is for the professional to help you) and start talking to a health professional over the internet, and it's confidential.
I'd can personally recommend this service as it really helped me when I had no one to talk to, they provided some unbelieveable tips and instructions on how to cope with things.
**Believe in the power of you because you are your own hero**
I know what you mean about doing work. I'm struggling myself at the moment. But with a lot of breaks and having done it in small increments over the week it's getting done. I'm a bit of a perfectionist...so I have to allow time for that as I won't be happy, unless I'm happy with what I submit.
Keep on chugging along though. Instead of thinking about what you 'should' be doing. Maybe take the time to meditate for 10mins or something to try and get yourself into a good headspace. I know when I have those thoughts in my head I need to take some me time before I can actually focus on doing work.
All the best to you.
Seen something fantastic on the forums?