Here is copied and pasted from The National Suicide Prevention Lifeline. You can also call them 1-800-273-TALK (8255).
Talking about wanting to die or to kill oneself.
Looking for a way to kill oneself, such as searching online or buying a gun.
Talking about feeling hopeless or having no reason to live.
Talking about feeling trapped or in unbearable pain.
Talking about being a burden to others.
Increasing the use of alcohol or drugs.
Acting anxious or agitated; behaving recklessly.
Sleeping too little or too much.
Withdrawing or feeling isolated.
Showing rage or talking about seeking revenge.
Displaying extreme mood swings.