Swimming - suggests you feel as though you are swimming through the depths of your subconscious and emotions. The ease with which you are doing this activity will give you clues as to how well you are navigating through those very complex parts of yourself within your waking life.

Unknown man:
Strangers - If these people are totally unrecognizable (they don't remind you of anyone you know)... they would represent different, and unknown, aspects of yourself. They are extensions and projections of your own subconscious, and personality.
Human beings (male and female alike), are curious, questioning, and have a need for information, and spiritual expansion. But... we all have masculine and feminine aspects (or sides) to our subconscious.
The masculine aspects would be the part of ourselves that we view as brave, strong, stubbornness, authoritative, logical...etc.
The feminine aspects would be the part of ourselves that we view as emotional, nurturing, tender, yielding, sensitive...etc.
When we dream, all the different parts of our 'inner selves' interact, and 'come alive', as though they were different people.

Shark - remember that the water in your dream is a symbol of your emotions and the subconscious.
Sharks are water-dwelling animals, and could represent unpleasant emotions or difficult and painful materials coming up from the subconscious, as well as your fears and problems in waking life. The shark also symbolizes feelings of anger, hostility, and fierceness.
If you are feeling some emotional upset, or are going through a difficult, painful, or unpleasant emotional period, then the sharks could be a symbol of what, or who, is causing the emotional danger, or upset.
Alternately, the shark may represent someone you see as greedy and unscrupulous. This person goes after what he or she wants with no regards to the well-being and sensitivity of others. The shark may also be an aspect of your own personality which exhibits these qualities.
Being bitten or devoured by a shark suggests you feel that someone is harming or cheating you, or threatening to.
Old dream interpretation books say that sharks may represent dishonest 'friends', or reflect financial troubles.

Bridge - There are many meanings that could be given to this symbol. The details in the dream are just as important as the bridge itself. The first consideration should be given to how much you travel. The bridge can be interpreted literally if it is a part of your daily commute.
On a more psychological level, bridges can symbolize transitions (e.g. transition from one stage to another, from one level of consciousness to another). Since most bridges are over water (i.e. emotions, unconscious), this dream could also be symbolic of your rising above your emotional difficulties or unconscious drives.

Climbing/Climbed - symbolizes a challenge in your waking life, or one coming up, the pursuit of goals and overcoming different problems. May also symbolize an increase in status.

Man was a shadow: Shadows - the unaccepted or repressed aspects of your own personality, feelings of being 'put in the shade', feelings still overshadowing you from a past experience or relationship, feeling inferior. Sometimes a feeling of dread or the fear of the unknown, and negative emotions.

Young boy (shark ate him) - being female and you dream of an unknown boy, it suggests that you are developing the masculine aspects of that character. If the boy reminds you of someone, he would represent someone in you waking life who has similar aspects or appearance.
Because you wanted the shark to eat him suggest you do not like who this boy represents. Whether it's an aspect of yourself, or someone else.

Languages - Dreams, in which someone is trying to communicate to you in a foreign language, which you don't understand, involve complex symbols. The subconscious often uses foreign, or mysterious, languages to express what lies within yourself that has never been thought about, or put into words. Much of our most fundamental childhood experiences were pre-verbal, and so they were only accessible and expressed as powerful feelings, and feeling responses. Dreams sometimes express these feelings, and intuitions about your wholeness, as strange words, or an unknown and mysterious language.
This dream could probably mean that you are finding hard to understand a certain person or to analyze your current problems. It may suggest that you feel the need for assistance or guidance.

Shotgun:
Gun(s) - symbolizes aggression, anger, and potential danger. You may be dealing with issues of passiveness/aggressiveness and authority/dependence. Alternatively, a gun can represent the penis and male sexual drive. Thus, the gun may mean power and impotence.

Shot the shark - To dream that you shoot someone, or something, with a gun, denotes your aggressive feelings and hidden anger toward that particular person....or the person that an object represents.
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Are you going though some transition within your waking life?
Are your emotions running a bit high lately...possibly threatening to overcome you?
Are you feeling powerless within a situation in your waking life?
Are you seeing an aspect of yourself, or someone else, that you really don't like?
Do you feel as though there is someone trying to take advantage of you or your situation?
If the boy represents someone you know, have you tried to warn them that someone is taking advantage of them, but they won't listen to you. So now you feel they get what they deserves?
Could you be wanting whoever is the boy, and whoever is the shark, out of your life permanently?
Is there a dreadful situation you don't want to face?
Are you trying to be logical, or sensible, about something, but you are finding it very difficult, or that you're out of your element?
Has something made you so angry, you found it hard, or impossible to put it into words...or you no longer wish to hear what someone has to say?

Hope I could give you something to go on, best wishes!

You're very welcome. Glad it helped.
Hugs,
J