I just saw your post and wish I wasn't having such a busy day today as I would talk longer but I'm just on for a short time but wanted to reply to you - and say welcome, by the way!
I did two degrees (a BA and D.Phil) as a part time student and it was tough. I had to take a semester off due to illness and that made the degree take even longer to achieve... I had a fried who pulled out of her studies after failing one course, and she was such a gifted, bright, intelligent woman that was a shame and a waste.
First, you may well pass the other assignment! And even if you don't do so well in this course, or even if you fail, it's not the end of your studies. High passing students are highly regarded by the academic staff and they will not want to lose you.
It sounds like you have had a lot to deal with the past year and are a bit burnt out? Can you find some ways to soothe or treat yourself, pamper yourself a bit, take some time out? Are there academic counsellors/staff you could talk to?
If you do want to teach, don't let one course stop you. I'm not sure from what you say if you are happy about being a teacher, but I agree, writing is no way to make a living at least in Australia...
I'm just wondering if you should wait and see how your other assignment goes.. as a high passing student, nobody is going to worry about maybe one course that you don't pass well in.
My brother is a very highly placed academic and he has straight HDs except for one Fail by a tutor who didn't like him! He says that F on his record has always annoyed him! He laughs it off now.
Don't know if I can come back today as I have a dog having surgery at the vet's - but I will come by if I can and others here may be of help to you. Don't give up is what I would advise! Find a way to take some time out for yourself if you can. Good luck!