Any tips on how to focus on studying while having a million thought?

When you get a stuck thought in your mind, as stupid or untrue as it may be, how do any of you block them out, or try to at least? It’s like my mind has another voice telling me making up the stupidest things?

My mind just starts racing with thoughts all day. I overthink aswell so I just tend to sit in the thoughts and can’t escape. I mostly have thoughts that tell me I don’t like the things I do like snowboarding or backpacking or if I even if I love my girlfriend. Deep down I know I do but then I start getting worried that the more I think these things the more they come true. Then I have tons and tons of more thoughts throughout the day and it just feels like I’m constantly having anxiety and constantly battling my brain over things that don’t even make sense. I’m only 17 and this is extremely hard and I feel like I’m wasting these teenage years. I don’t know what to do or where to go. I’ve picked up reading my bible and praying more but the thoughts persist please help.

so I feel like I’m finally having an academic comeback after years of failing & I’m currently looking at pinterest for that motivation. there are videos that are helpful tools for college students like websites that read chapter books and summarize/create notes & it seems pretty cool. but I somehow deny using those tools bc it feels like I’m cheating. my mind is like, “no, you will study the TRADITIONAL way (which idek what it rlly is)” I don’t know why my brain is doing this to me. I feel like these apps could be beneficial to my learning. what’s ironic is that I literally googled all my assignment answers for one class at the last minute to get some grades in. this is a retake class but because I was so behind on everything, I just looked up the answers. so that really does count as cheating. like bruh 😭 I did it to save myself from a bad class grade. I’m definitely going to study the rest of this semester. I have officially began taking notes and actually doing schoolwork. someone help me!!! these videos look like great resources but my mind is telling me otherwise. another thing is that I’m still lost on what to major in. I keep changing career choices and my head’s gonna explode. there are so many things I wanna say but I don’t want the post to be long. I just want to get good grades and understand the material!!! someone help me >n<