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Sorry to hear you are having a tough few days. When we are under stress our body goes a bit basic on us; it thinks your life is in physical danger and so gears up for the "fight or flight" response which is a state of preparation for sudden physical activity. So blood flow is directed from "non essential" services such as digestion (hence the nausea), concentration, memory, hair, skin etc to the large muscles via adrenalin which makes your heart beat faster to get the blood moving there. Unfortunately the more this state persists (i.e. you feel stressed) the more the brain thinks "i'm right to do this, look she is still telling me she needs more" and so the cycle emerges. Bear in mind originally this response was only originally designed for very short response periods when you would haev been physically active so wouldn't have noticed the physical sensations. Usually we find passive methods to reassure ourself, food etc but these are only ever temporary and don't really remove the underlying trigger.
The answer? A series of deep breaths etc; physically it tells the mind you have enough oxygen so starts switching of the response mechanism (think of smokers who say they feel better after a cigarette.. the deep inhale has something to do with it). The power of telling yourself it is all OK and you can cope is also understated. Have a look at MIND.org at their anxiety pages for some tricks and also livinglifetothefull.com is an excellent website if you are feeling a bit low and want to explore behaviour changes to break old pattern.
Good luck - it will pass!
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