1 year old Shih-tzu Maltese suddenly fearful of things?

He is suddenly showing different fears. Last week, we walked in the park and at the other end was an empty large flower pot which had him shaking. Last night and today, he went past a stack of sod in the neighborhood clearly very scared. Not sure what is going on and if something has happened. Not sure how to help him. Not sure how to investigate if something happened. Otherwise, he is the most confident dog