my third transition (landing) last lesson left me 180 degrees the wrong way
I'm not sure if I've completely understood your problem, but I do know that ALL students seem to find the last bit of the transition from forward flight to the hover very difficult at first. Everyone's different, but I've come to the conclusion that there are several reasons for this....
1) Frustration. You've probably got the upper air work and possibly the transition from hover to forward flight roughly right, so why is this holding you up?
2) Exhaustion and overload. It's right at the end of the circuit. You've done loads of unfamiliar stuff in the last ten minutes, and now you've got the most difficult bit to do.
3) Fear. Your instructor is probably on at you about carb heat, aiming points, going forward and down, looking out for other aircraft etc. It's just dawning on you that this stuff is potentially dangerous.
4) Up until now you'll have rarely made any large pedal movements; it's all very gentle. But now, as you come to a hover, you lose translational lift. This means you need a big movement of the collective, which means you have to have an equally big pedal movement. Was it in coming to the hover that you had your 180 degree turn; it wasn't clear? Anyway, there are two ways of coping with this...
a) Just practise till you get it right.
b) Slow down and pull in power gradually, and if your instructor doesn't mind, come to a hover-taxi rather than a hover, then slow down to a hover. It's all a lot gentler and easier, and gives you time to think.
5) The main reason for all of the above....
You are trying to run before you can even stand, let alone walk. Relax. The people who find helicopter flying easiest (correction...least horrendously difficult) are the ones who don't try to hard, who aren't ambitious or success orientated, but just have a laugh and enjoy it. 12 hours is nothing, and practice is all it takes.
So....have fun!