Physics SL?

So I'm at a pretty bad situation; I take physics SL but I have come to actually be very dismotivated to study for it since last year, so now I need a full-on revision from topics A to E. I've no plan, all I know is I start with theory and then when I understand it I begin trying to practice, and I fail every single goddamn exercise. How do you successfully study for physics? This is making me lose braincells and I don't know if I'm not trying hard enough or if this is the wrong way to study for it.