just look at this day in a positive way...
1. You made it halfway through the day without hurting yourself. Tomorrow try and go a little longer until you can go 24 hours without, and then go without it completely. Just tell yourself: today I will do better than yesterday! And if you do, then reward yourself. You just need to wean yourself off of your addiction.
2. You got some work done today. You lifted some boxes.
3.You didn't go to the library today, but you planned to. You had a plan and that is great! Maybe you can make another plan/goal to go tomorrow. Try and make plans to go out so you will forget about SI. You could talk to someone on the phone if you want to stay at home. Maybe take up a new hobby to distract yourself.