For the football game, I would encourage you to have a 'game plan'.
All you have to tell your pals is 'I am not drinking today'. Then order a pop, or a coffee. I believe that in the early days of quitting, it is too much emotional work to have to do the whole song and dance about the damage of alcohol in your life, etc. Later for close friends, you can be more explicit if you care to.
If you think the game is going to be too hard a test so soon, consider giving your ticket to a friend. Sometimes caution helps a person to avoid shame and regret.
And I second the recommendation that you find some sort of program for support. AA meetings are far more helpful than you might think from the outside. Far more. But if you are reluctant to go to a meeting 'cold', try something else. Counseling, medical appointment, talk to a sober person you know; don't try to white-knuckle it all by yourself. Help is available!!
Best wishes for success in this and for a bright future!