Try going back to the basics? It's going to be hard going on to y2 if you don't have a solid foundation to work on. Revise using old materials, memorise all the mecessary formula, look up practice questions with explained answers or watch video tutorials, and maybe ask a classmate or teacher or someone who feels confident to explain it to you. Teachers should be happy to help? If not, there are tutors or student mentors (if you have them at your school). Once you have that down, it should be easier to build on top