This mightn't work for some people. But it's an idea.

Make plans to do something with someone the next day. This might discourage you from doing anything because you think how would this person feel if they were planning to see you and were told you were dead. Or, if you go to hospital, imagine how stupid you might feel telling them the reason you couldn't catch up with them was because you'd gotten yourself into hospital. I think it's harder to consider suicide when you have people around you. Because telling yourself 'i'm worthless' doesn't work if people are willing to spend time with you, neither does 'i'm alone' or 'it's hopeless' if there are people who are willing to talk to you about it.