Well I always can't seem to keep up with journalling... I'm bad at building habits and breaking bad ones.
No it's not. It's just that you maybe following the wrong methods. Try different methods and check what works for you.
I'd say:- just write down the reasons you want to quit PMO. Ask questions like:- do you really want to quit? Or are you just thinking or expecting your next relapse? Just be firm and it'll be easy.