What does this mean? today, put away the diplomat in order to protect your own interest.

This could be a horoscope reading.

The sentence: 'Today, put away the diplomat in order to protect your own interest' means that you should put your interests and well being first, regardless of what people think about your behavior.

Sometimes, you tend to everybody else's needs first, forgetting your own. You want to behave like a diplomat, be fair and not offend anybody. This way you would be probably liked but unhappy. So today, be civil but don't go out of your way to be friendly or welcoming. Not everybody has to like you and you are under no obligation to love the whole world either.

because they were not just any seashells they were sally's seashells