On one hand you mentioned that we are insignificant akin to dust. On the other hand, you said look back through out your life and see how you overcame challenges. See that there has been a guiding hand. The question is, if we are insignificant, why is there a guiding hand in the first place and if there is a guiding hand, is it fair to say that we are insignificant?
Till you know that there is a guiding hand you are really insignificant. But once, you know that there is a guiding hand and you are part of it, you become very significant.
Charcoal and diamond are made up of same material. Coal in itself is insignificant but when it becomes a diamond, it becomes very significant. Truth is always contradictory.