Can you not TRY and finish it and work your hardest but if you don`t finish then defere, it would take some of the stress away of having to finish, but I don`t know how ur uni system works. Like you said "to get extra time and finish this and then spend my time once graduated working on a portfolio in my spare time whilst getting a crappy job"
Also huni, if you are thinking of teaching (i know uv said that before) then your portfolio probably won`t count towards u getting a job and you could use next year to do your P.G.C.E??? Just another idea. (think of the holidays that teachers get!)
Really though none of us can decide for you. If it were me, I`d have to finish it this year just because I would be angry with myself if I stayed an extra year. (even if the work wasn`t as good as it could be). There are so many factors that could get in your way again next year; You could end up being ill again or get bored at repeating it all and give up on gaining your degree completely.
I think the best thing to do is seriously think about what you want to do in the future and talk to the docs/student advisers.
I truly wish things would get easier for you, sending you massive massive hugs....remeber this won`t last forever. It might seem like the be all and end all but a few years, even months, down the line you won`t be thinking about it. I mean who asks how you did in GCSE`s/A levels now? Hardly anyone!
BIG big big HUGS,LOVE, and Fairy wishes ! Keep smiling. Lets us know what u decide.