I have read somewhere that you should always put at stake what you are willing to lose. I'm sorry for the loss you've had. "I feel that knot tightening in my stomach - the stiff upper lip" I have also experienced this feeling that you have described perfectly, although not by play or investment. I hope there is enough left over to start over. Greetings, @tarazkp.
The knot comes on the back of many events - money is not the worst of them.
Maybe it is good to get kicked every now and then - though I am a little tired of the beatings :)