sport role in quiting

Hi friends

at first sorry for my English. well I am 34 and I was a chain smoker (30-40) for 12 years. last week in Aug 23, my birthday I gave myself a birthday present and I quit smoking. the first day was so hard and intolerable then I decide to do some sports. I went to mountains and walked for 7 h. the next day I was so tired and I was feeling an heavy pain in my legs and back due to spasm. But it was so pleasant. The next day I went to gym and play football. During 5 past day I had no time to think about smoking and I did not feel any withdrawal effect. I sleep and breath  very well and  I want to continue this method until I forgot smoking totally.