The same happens with everything in life. It comes and goes. But if we compare emotions with the storm it can be hard to stay still when it hits.
The best advice for that is from a friend of mine I met on the Peace Summit in Hungary. He said we couldn't fix the roof when it rains. We needed to wait until it stops so we could see clearer, what to fix or if it needs fixing. So when the storm hits the best thing to do is... nothing! It would be silly to want to stop the real storm, wouldn't it?
Learn to observe. Don't judge. Get into a good place and wait.
Have you even seen a storm from the window of your house? You, covered in blanket, having a nice cup of tea, reading your favourite book... you just observe a natural force that does what it is meant to do. It might hurt only if you go outside. So stay in and rest. The storm will not last forever but will wash away all what needs to go. Your task is to LET it go.
And after a while, you will come out into the freshness of after-storm air, into the bright shine of the sunny moment and will realise that you have always been here...