Act,im a sec 3 student myself too.
I didnt do pretty well this time round.
But in your case,i think lets say IF you do get retained,you have
to take it easy.Many people tend to look on the negative side,and
think that,oh, "retain means waste one year!"
but look,so what even if you're promoted to sec 4.
for the "O"s, 75% of the syllabus is mostly tested on sec 3 work.
Thus,your sec3 work is fundamental. This means,you must understand
your concepts well enough. That means,even if you do get promoted
to sec 4,you may find it quite a task to cope with your schoolwork.
Besides,this does not easily gurantee a good pass for your
Os.
Look at it optimistically.
Anyways,about your eng,feel free to drop by any libaray or spend a
day at kinokuniya,the bk store at Taka,it's really big and huge and
has got a whole loads of gd books.
As for your handwriting,i guess penmenship does't help yeah? Maybe
you could try copying your text during the hols. It's two birds
hitting with one stone. Firstly,you get to improve your
handwriting.Next,some people find it easy to remember by copying.It
does help,you know?
All the best!!!!! 
