Saturday feeling down.

People often say they feel depressed, I wonder if they know what it means and how it feels. Today I feel ghastly. I dont want to bother with anything. I want to just get to bed, I feel a burden, useless and start dwelling on the negative things in my life. I start to worry about the future, not anything in particular money, health the future it all seems black.
I feel on the scrapheap - at 44. I worry that people think I am on the fiddle, I hate it that I look so well, and feel so crap. I see someone in the street and they say how are you - I generally say fine- most people dont really want any answer.
Actually I am stuck in a year long depressive phase of Bi-polar Affective Disorder - how are you.
Everything aches, everything is too much effort I am scared to say how I feel in case I taint everyone else. I dont know what to do.
We go to Cheshire Oaks an outlet village. After a 20 minute journey that took nearly an hour cause of the rain I feel yuk. Lunch in a food outlet in a food court. Yuk.
Then into a shop to purchase a waterproof jacket. I try a XXL and it doesnt touch. I run out panicking - is this the return of the fat bloke. I sweat and  breathe quickly. I go to the car and calm down. I feel really down and black thoughts darken my horizon. I fight it and go to another shop. It fits, snug but zips. Then I look and see its only XL. The 2XL fits well check it out.