idk if this is even anxiety

I have this thing where I always imagine someones about to die. Like especially at night, if I hear a noise from any other room in the house I go down this spiral of thinking about how they could be having a seizure or a heart attack etc. I can’t sleep in the same room as someone because if I can’t hear them breathing i worry they are not, if they aren’t moving i’m worried they never will again. and it’s kinda gotten to this point where i’m constantly worried about people dying and about how i could’ve stopped it if I would have just made sure they were still alive. I drive my self insane with these thoughts. I find it really weird because normally i’m the most chilled laidback person you’d know. It kinda started after i saw my teacher (online skype lessons) have a seizure over skype and couldnt do anything about it and then when people came in to help her i had no idea what was going on because hey were all speaking a different language (she’s fine). I feel like that was not that bad and it happened months ago so i feel like i shouldn’t be worried about people dying. (don’t know if that’s why i am always thinking about this but i think it could be the reason why)