How to deal with obsessive thoughts about how life doesn’t matter?

It’s either “I’m having so much fun, I love life” or “life is meaningless and there’s no point in doing anything”. It’s horrible and it gives me so much anxiety I can’t handle it. I keep obsessing over philosophical stuff like our existence and the origin of life etc, and it’s really scary. It always ends up at “what’s even the point”. I can’t do any hobbies like painting or making bracelets because “what’s the point”. I’m doing all I can at the moment to get better and stable so that I’ll be able to go back to school. But then, “what’s the point”. It’s all I think of. When I’m distracted I’m super happy. I was out today and I had so much fun. Then I came home and was hit with that stupid thought again. I could probably post this on the mental health or anxiety subreddit but it’s the black and white, all or nothing, obsessive thinking that’s making it bad. I know it’s normal to think like this sometimes but it’s horrible that I can’t get out of it. I could deal with it once in a while but it’s ALL THE TIME. I can’t distract myself constantly..