I had a similar situation in my second year at Bath: I was ill for a prolonged length of time in the first term. With my studies being severely affected, but me being very stubborn and determined to continue, it looked like I would probably pass the January exams, but with significantly lower marks than I was capable of (as indicated by my first-year results). Although the department was very supportive and did all they could to help me, it was very simple: if you have passed the exam - i.e. got at least 40% - then that is it. You cannot re-sit under any circumstances. The more appropriate route was to suspend studies for that year, and restart year 2 the following October.
Whilst I suspect your circumstances would have qualified for mitigating circumstances. However, in the world of universities, timeliness is key. Even with the best will in the world, if you submit your mitigating circumstances now - with results having been released (which means exam boards have met), I severely doubt you will get anywhere. For starters, the university will question why you didn't submit them previously - after all, in the eyes of the institution, you had plenty of opportunities to submit the mitigating circumstances: before exams; straight after each exam (I think you have to do a separate form for each exam in this case!) or even in the intervening weeks between exams and results being released.
Further, I suspect the uni will see the more appropriate course of action (that you should have taken) as suspending for the whole year (BEFORE taking any exams) and restarting afresh in October. (As in my case above).
Depending on how far off a 2:1 you are, you can still get the degree classification - through hard work: your 3rd year will count more towards your degree. Look through your course handbook or similar to find weightings etc.
Also, I would assume that your marks are way down on those of your first year? If so, it will be obvious that something happened. (Obviously, this would be helped if you apply to do your masters at the same uni (in the same department). So, if you work hard in year 3 and are prepared to give some explanation in your application, a masters degree is not completely beyond the realms of possibility.
BUT this requires you to take the right actions: if you feel like you won't succeed in the way that you want to because your conditions are still hampering you, then consider taking a leave of absence until you can succeed as you want. If you continue, and something else affects your studies, then you need to submit the paperwork for mitigating circumstances IMMEDIATELY! (Just telling a tutor is not enough!) This applies until the end of your course!
The best advice anyone can give is to go and talk to a tutor: your personal tutor; welfare tutor or director of studies. But do so sooner rather than later.
I'm sorry this post is so negative. I know it seems will read as if I am being harsh on you...I'm really not. University processes are confusing at the best of times - and worse when you are ill. I understand how you feel. But, at the same time, I don't want to give you false hope. So, I'm giving you my honest answer.
I hope you continue to get better, that you manage to get the degree classification you want and succeed in going forward to a masters course.