How do you explain anxiety to people who claim to know what it is, but tell you it's all in your head when you have a panic attack?

Everyone I know gets really mad at me when I have a panic attack and tells me I’m overthinking it, or it’s all in my head, or to just stop overreacting.

I keep thinking of it like this “If you went up to someone with asthma, who was having an asthma attack, you wouldn’t say “It’s all in your lungs. Just cut it out and breathe normally”” like we know asthma is serious and yes it’s different on the level that people can die from asthma attacks, but it’s the same idea.
Are there other ways to explain what it’s like to have anxiety and panic attacks without getting super personal?