running question-when will I feel good and enjoy it

Good day all.
I read a few posts and you all ROCK!!
I recently got off of anti-depressants and I am feeling extremely exhausted and fatigued. Not to mention that I am a stay at home mom of 3 year old triplets.
Everyone keeps telling me that excercise will help so I will give it a try.
I am so tired all of the time. I need some support on this. TELL ME to get my ass out there NO MATTER WHAT!!
I am going to start with running/walking around the block one time a day and slowly work my up to 1 mile and then who knows. Once I like something, I usually dont stop so I am hoping to really dig this and change my life.
I like the thought of running because I can open my front door and start, I don't have to drive somewhere and I dont have to go into the dark basement to excercise.
So when will I feel the great effects of this excercise stuff?
ANY support, thoughts or suggestions are GREATLY appreciated!!