Advice? Am I attempting something impossible? (Behind on A levels)

I'm a year behind my current age group because I spent the entirety of secondary in hospital, so to catch up for that lost year (I know people will say I don't have to catch up but it would really make me feel better about myself due to personal struggles so that's what I'm doing), I'm doing distant learning for my A levels, studying both AS and A2 modules simultaneously over this one period instead of over two years (planning to take the exams independently in June 2017)

I'm doing two of these A levels, History & RS.
With History, I've done about half of the assessments, and I'm starting to work on the coursework essay that contributes to your final grade. I'll definitely have that finished by March when it's due.
With RS, there are less assessments, and no coursework essay, but I've only just started it (took a while to set things up with the providers).

My History tutor said I'm attempting mission impossible, but after submitting some TMAs (I've got A-Cs so far) he did say I really show potential & ability (although he is still very skeptical over if I will be able to prepare for the exams in time & pass, because he says you need to have a seriously broad knowledge not only on the subject but on how to write about it too).
My RS tutor doesn't really communicate their opinions on it, so idk their perspective.
I am not overtly insecure in essay writing in general though, and I have a history of doing well in that sense.

Baring in mind I'm at home all the time as I'm still recovering, and literally have the entire day to study if I want to (as fast as I want to as well because distant learning give me the entire course upfront), do you think I can study two A level subjects almost from scratch from now, for June, and do decently? I'm doubting myself so much purely because no one else thinks it's possible.