The Tank

Imagine this:
   A big tank full of fish like those big ones you see at the dentist. (Also why do dentist have fish tanks in the waiting room?  Like in Finding Nemo too.)  
   A nice clear tank with different kinds of fish. That's my brain, most of the time. Clear and full of ideas and thoughts and feelings and everything(the fishes).  
   But then on the days I feel the sadness come, it isn't super clear anymore. The tank is getting dirty. The fish aren't so friendly with each other anymore. Sometimes they even eat one another. Then without warning a black tint seeps into the tank and starts intoxicating the fish. (Who put it there? Who put the darkness & negativity inside me?) The fish are slowing down. The fish are sick. Some aren't breathing. Some aren't swimming. But they're all dying.  
   And the lady at the front desk at the dentist office finally sees the blackening  
water in the tank. She's tries to adding some clear water but the black tint is too thick. The tank is going to overflow, and she's scared and closes it up and just watches the murky water tighten up against the tank's glass. (I can't stop the sadness from coming, I feel it in my heart. And my head knows it's here.) The glass feels the pressure and it's starting to crack. The fish who are barely alive are being pushed against the glass; they just want to live. (I just want to live.) Without warning the glass breaks and explodes all over the white dentist floor. (It's settled inside me, and the sadness is here again.)  
  The black tint spreads on the floor and stains the white walls and white chairs. The white clean lobby is dirty and the fish are flopping on the floor out of breath, waiting for death. (What do you do when you don't want to live but you don't want to die?)  
  And that's what depression looks like inside my head. No matter how I try to clear my head, sometimes the darkness spreads too fast and I become contaminated, and toxic to myself.
  Somehow, the lady at the front desk cleans up and replaces what she can, although the floors will remain a shade of grey.  
   All I gotta do is learn to catch myself before it happens again.