New habbits - how hard can it be?

"They" say that it takes 21 days to establish a new habbit.

Well - duh!

I decided, aproximately 5-6 weeks ago, that I would wake up one hour earlier every morning and take a long walk. This due to improve my health, loose some weight and become perky.
So, up I go... almost every day, weekends are bad though and mornings with rain and mornings in common... What to do?
It is totally amazing how fantastic my brain is to conjure up excuses to not go up from my cosy bed five in the morning. It can say to me things like: "You were so good yesterday, do you have to be that good today too? You can go up, by own means, but go to the living room and make some situps instead. Why go out in that rain, hun?"
Sit-ups my ass.
So I have to get angry and yell at me. I do it quietly though, not to wake up entire household with cursing. Somewhere from inside this furioso arises and starts to yell: "You bloody old bag, get up your ass NOW! Out and walk, in fresh air. Get up your fat ass...!" Etc. So I get so ingredibly angry that I bounce up from my bed and when I'm up it becomes quiet. Well, I usually go up and not back in bed.
And sometimes I don't even know that I'm awake before I get to the point of uphill on my morning round