I can empathize with you. Over the years I've gone through bouts of insomnia where I can't get more than 2-3 hours of sleep per night for multiple nights in a row.
What I've learned is that all of those sleep hygiene tips and rules that you hear about (no screens before bed, keeping a set routine, journaling before bed, etc) are nice for people that are interested in improving their sleep, but if your primary cause of sleepless nights is anxiety, then they can actually be counter-productive. Why? Because the more things you do to improve your sleep, the more anxious and annoyed you feel when you're lying in bed awake. It's a vicious cycle, and OCD absolutely LOVES that kind of thing.
My best advice is to focus on how you can improve your life during the daytime, and good sleep will happen naturally. You will have nights of terrible sleep now-and-then, and that's okay. Whatever thoughts you have while you're lying in bed awake are honestly irrelevant; all that matters is that you feel anxious, which is keeping your brain alert and awake. Nothing more, and nothing less. When it happens, don't be so hard on yourself. Instead, take it as an indication that it's time to make some changes in your life.
So take some time to investigate the anxiety, and what is fueling it.
Is it POCD? Therapy will help that over time.
Is it work or school? Start developing a plan to reduce the stress caused by those things, whether it's talking to a teacher/manager, being honest with yourself how much work you can handle, or thinking about getting a new job.
Is it related to friends/relationships? Find people you can talk to that you can trust, and work on resolving whatever conflicts are bothering you.
And remember, anxiety will never 100% "go away," nor should it (it's an important emotion for our survival, after all). The idea here is to reduce the unnecessary anxiety caused by our modern way of living.
Another thing that is proven to improve sleep, which is NEVER mentioned in any article or video about sleep, is to spend time helping other people. Whether that's talking to a friend who is feeling down, or doing some charity work, engaging in any sort of pro-social behavior is a natural way to increase your overall happiness and contentment with life. Make a habit of reflecting on the ways you've helped others as often as you can, and also reflect on the things you're grateful for. I know that sounds like a lot of fluff, but there is serious neuroscience that backs that stuff up.
Hope some of this is helpful for you.