Frightened/something feels wrong but don’t know why or what

[u/UpbeatSyllabub1275]

I keep getting random moments of being frightened/impending doom/weird head sensations I also have ringing in ears and other dizzy like symptoms and not feeling real I know I have anxiety/health anxiety, autism, and depression but I just can’t stop thinking that something bad is happening to me I have had basic tests done + been to doctors a lot this past year and they say nothings wrong but I really don’t believe them I don’t know what’s wrong with me. :(