Well I do Religious Studies (Philosophy and Ethics) at A2. I covered all those topics you mentioned last year apart from miracles. I found Utilitarianism pretty easy, but it depends on the type of utilitarianism your covering which i suspect is both Rule and Act Utilitarianism, and I found the other topics you mention ok. For me it was just basically going over my notes talking about it with other people in your class always help. Why not try asking you teacher to go over a few things with you, if you are really struggling.
To be blunt - nothing gets easier at A2. You might find you get more used to how to structure an essay, and find you're covering simliar topics so understanding it is easier. If it's taking time away from your other subjects, then drop it. There's nothing more horrible than constantly finding a subject a struggle! Are you taking 4 AS levels?
Hmm.. I know the feeling. Tricky, doesn't sound like a good teacher, if you're finding it too hard then it might be easier on balance to drop it - would gain you some lovely frees! What other subjects are you taking? Just coz philosophy looks good, was wondering if your other ones are as impressive..?