Exercise not because it will change you magically after x days. It won't. Exercise because it's good for your health, it's a good way of building friendship if you do it with someone else.
I started exercising every day for half a year and sometimes still don't want to go. Addicted to exercise? No.
Improved mood? I still feel unhappy every day for not being in the right place, the right tract to my dreams. Exercise doesn't make feel better.
But I do feel less guilty when eating food I enjoy. I want some nice hot food so much during this cold winter, and I am glad that I do exercise so that I don't gain so much weight from that.