Remember it doesn't mean your school 'bombs out' if the highest mark is only 12/15. In terms of school work, this only contributes to your internal RANKING there have been numerous threads on this around these parts of the forum
Basically the best situation you can be in right now is to place as high as possible in the internal assessment rankings. It doesn't really matter if you score 10/15, if everyone scores 9 or lower it still places you first.
Also i wouldn't recommend just writing random essays because the english syllabus is (deplorably) very strict and there'll be specific techniques they'll be looking for in exam responses. What you could do is try to improve what you have already prepared/done for your first assessment and maybe find somebody who can read and give you feedback on this.
Also, if you know what modules and texts you'll be doing next year (you seem to know you're doing antony and cleopatra judging by your past posts) then you can probably prepare something for this even if it's just background research and a selection of possible related texts.
Find out as much as you can from your teacher before the holidays begin and just work as much as you need from there.