I definitely felt like you in the beginning. It was so hard to stay in the "now." I was constantly struggling with those forever thoughts and they would always rock my world to almost caving in. How I did it in the beginning -
I white knuckled it. I had a reason and he, that reason, is in 1st grade. I had to find reasons outside of myself because I didn't like myself enough to want it to make ME better. I can honestly say I now like myself enough to know that I want to be sober because I want to live and not die. I don't want to punish my mind or body in that way any more. I am grateful that I was provided with any reason in the beginning because the longer I was away from the stuff the stronger and clearer my thinking became. I also used the 24 hour method. There is a thread called "Don't Quit" and I like to post my 24 hour promise there.
Have a back up plan and use whatever you have until it becomes a new way of life. No more hangovers, no more black outs, no more arguments over stupid stuff, and no more loss of dignity. That's what sobriety has given back to me. Hope this has helped in some small way.