That has been so annoying for me. It happens out of the blue, I'll be sitting around and suddenly, I'll feel a knot in my stomach and then BOOM! My stomach starts heaving and I burst into tears. And then I try and get control of the situation by taking a deep breath. I had to explain it to other people, that it's just this annoying little thing that happens sometimes and I'm not depressed or sad, I have no control over it.