Health anxiety - brain tumor

Hello, 3 and a half months ago I was working pretty hard on my school project (editing a film) and my mother told me that for the last few days I am working a bit too much and I should take a break and also see the sunlight. I kept working but also felt guilty that I am going against my health with all that work. Suddenly I got a weird anxiety sensation inside my head (it felt like something is not okay with my head) and a thought occured that I might have brain tumor. Since then I couldn't really stop thinking about it. It was like a mix of feeling guilty that with all that cognitive overload I must have had caused myself a brain tumor and also as I am strongly a magical thinking type of person believing in body intuition I couldn't really deny the option that what if the thought was just my body intuition trying to warn me. I couldn't 100% say that it's just an anxiety thought. Few days after that it totally got me down, I was totally depressed that I'm going to die and the insecurity was just unbearable. Ever since then from time to time I remember this situation and immediately get paralysed from fear. It got better when some time passed but then like a halth month ago I heard a story about a man who had a brain tumor for 10 years and didn't know about it...that just totally destroyed me again. The worst about it is the insecurity that you can't just see inside your head and also the feeling that if you have such disease why aren't you taking any action and go to see the doctor. Like you're just letting it be while it's slowly growing. But I know that if I get my head or any kind of organ checked once due to OCD, I will want to do it everytime I am in this kind of state. Please help. How to deal with this state? Also good to mention that one or two days before this thought occured I got an email from a charity organisation that thanked me for my small monthly contribution and shared a story of a little girl having a brain tumor whom this organisation helped. And the day or two after this thought a word tumor was spoken many times in my family because of our dog who was going to be diagnosed with the tumor at that time. Thank you for any advice.