One of the most frequent dream themes is that of anxiety in some form. This may not be because most dreams are about things we fear, but simply because we remember those dreams more than a bland dream. In our dreams the things we fear are only our own feelings. Of course, the dream may be about a snake, or car accident—things we fear which are not inside us. Even so, it is our feeling about the snake or situation which disturbs us, and these can change, even though the snake remains just what it is.
If we cannot meet our feelings of fear or emotional pain we are controlled or trapped by them. Sometimes we need the help of a professional therapist to meet what we fear, but many fears can be met by using simple techniques. See woljunder animal, dream processing, premenstrual tension.
The dream symbol you are looking for is absolutely there, try searching the symbol one by one.