Many here will be having BOTH physical anxiety from hormone volatility and psychological anxiety from what you're telling yourself. The latter also leads to physical anxiety but it also can escalate to a much higher degree due to the subconscious listening to what you're saying and presuming you're in true danger - hence the desperate fight or flight feelings.
The physical state is likely due to adrenaline surging as the brain tries to force the heart to beat faster etc. when there is an unexpected hormone plummet (or rise in early peri when oestrogen can over-stimulate).
To stop the emotional escalation it's important not to distract and to face up to what you're saying to yourself and then rationalise it. So you can accept hormones can cause the initial physical anxiety and then also accept the sensations and deduce that nothing terrible is going to happen as it's the self talk of "oh my god, I'm terrified, what is happening, I'm having a heart attack!!!!" etc. that creates the psychological anxiety on top of the physical. This can be habitual from the subconscious where you don't realise you're thinking it. To over-ride it you say to yourself "it's ok, I'll be ok, it's not the end of the world, it's a really uncomfortable feeling but I can stand it" etc. These are true statements unlike the previous and will start to calm you down. They can't help the hormonal anxiety but it will help you cope with it by not going into sheer panic.
It will feel unnatural to think calmly when your body is so stressed but with time and repetition it will form new habits and you will slowly gain back control. Also breathe out strongly and for longer than you breathe in as when we panic we do the opposite and start to hyperventilate. Pushing air out will also reverse physical panic brought in by worrying.