my boyfriend tried to commit suicide today

I'm really in shock rn. I really can't believe this is happening. My boyfriend tried to commit suicide this morning. He told me he just wanted to end all the stress and frustration of college. This is his first year of college and mine as well. He said that he tried to overdose on pills but then thought of me and he spit them all out. I'm really on edge right now and I'm very scared. He won't text me or answer any of my calls. I'm very very scared and I don't know what to do. He has an older sister and I don't think she knows about his suicide attempt. Should I tell her? I really don't know what to do at this point.