I heard b'shem the Chassam Sofer that when Haman slandered the Jews to Achashveirosh and said "Yeishno Am Echad..." (There is this one nation...) he was saying "YeShanu" (they are sleeping), meaning the One Nation is now sleeping in their achdus, they are spread out all over the globe and have no unity, and now is the time that we can get the upper hand on them. Esther's answer to Mordechai was to "gather the Jews together" and rebuild the achdus, as they all prayed for each other's lives.
We are weakest and most vulnerable when our connection to each other, to the Torah and to Hashem is broken, but when we rebuild that union, we get Hashem back on our side and through Him become invincible, for He guards us saves us from our enemies.
Achdus, true unity, is not just a warm fuzzy feeling to be hidden away in one's heart. What builds our people's connection to Hashem and the Torah we received through Moshe, is the achdus we build through being "nosei b'ol im chaveiro", putting our own shoulders to the work, to help carry the burden of our friend.
With all the Tzedakah given out Purim Day, we had a tremendous outpouring of Achdus. Now that we are all out of money, we can still move on to get involved in the lives of struggling families, children, parents, the lonely and the sick. Visit, get involved in tzedakah organizations that pack & deliver food to the needy, be a Big Brother or a Big Sister, offer to tutor a child from a poor family - ease the burden any way one can, there are so many ways that have very little to do with money and have everything to do with time. (And of course, true chesed begins at home, with our wife and kids!)
We addicts suffer from isolation and poor self image. We can get ourselves out of isolation and really understand our self-worth by finding ways to be of service to our fellow Yidden. And even though, at first, we might be doing this for our own needs (i.e. therapeutically), eventually, it will awaken our hearts to be doing it more for their needs and less for my own - Mitoch SheLo L'shma, Ba L'shma.
By finding new ways to see ourselves in a positive light, we can combat the negative self-images that feed off of our R.I.D. (Restlessness, Irritability and Discontent) and lead us down the path of acting-out and other self destructive behaviors. When I become valuable to other people, I have more value to myself, and I rebuild the shattered relationship not only between myself and Hashem, but between Hashem and the rest of our people. And I can learn Torah with more excitement and earnest desire, because I feel closer to Hashem and feel his desire for me.