It is very hard to bring yourself to drink the SN, especially knowing that afterwards it may be the end and there will be nothingness, despite the fact that nothingness is your goal due to your agonizing life. I think it is SI that causes this, knowing deep down that the SN can kill you your SI has been influenced as well, now it knows to stop you from drinking it but you can beat this SI since it isn't built into your body, it is very hard to do that for some people though.
Anyways, I wish you the best with your future plans and hopefully you can manage to take your mind off of these negative feelings that you failed your attempt. I know failing an attempt is very disappointing because I have failed nearly a dozen attempts so I understand your situation. Take some time to calm down and recompose yourself before trying again. Best wishes.