Feeling alone, defeated and on day one
Get to a meeting today. It helps. You aren't defeated. In fact you were defeated for a long time while you were using. Today you took the win. You decided to fight back. When you got knocked down you didn't stay down. I'm proud of you for that.
Day one is a huge accomplishment!! You should be proud of yourself. I agree with Steve S whole heartedly. Stay strong it only gets better 

Day one!!! It’s a great start. “I will not drink/use today”. Really good that you have made this decision. Reach out. There is no judgment on this app, we have all been there.
You need community. Other people like us. Go to a meeting but stick around and talk to someone. Go get coffee. Find a temp sponsor if you dint have a sponsor. I drug my feet for 10 years not sponsoring up. It was my way of keeping the exit door open.