It's okay, it's a natural feeling. It does take time to treat it with ease, but just need to be conscious about it. Gradually it will be easier when such things happen. As of now while it still affects you it is best to try and find a distracting activity. But just try to keep in mind that it should not affect you as badly as you think it will. It's just one small step in many many big steps in life, it's not as significant as it sometimes seems :)