Advice?

Hey all, I’m currently a senior taking AP Precalculus, so far, I have found the class to be incredibly difficult. For context, I took Algebra II my sophomore year before switching over to statistics my junior year (a mistake on my part which I believed has set me back). After Thanksgiving break, I have a test I need to take and I made the questionable choice of attempting to learn from Algebra I all the way to Algebra II. But I am finding the process to be difficult, and a large part of that is causing me to feel majorly depressed. Just relearning these concepts is making me mentally drained every time, but I try to push through in hopes that I’ll come out with a greater understanding. But I think I’m making the wrong decision. It has never felt so frustrating, tiring, and depressing before. I’m honestly disappointed in myself. Anything you guys could say? I’m already due for the AP Precalculus test, so I don’t think it’s looking too bright for me 😂