Is it PCOS or just stress and sadness?

Amber • I have an amazing boyfriend and I`m 20
Hello Ladies, I'm 18 years old and I have been wondering about this, I haven't had a period since the beginning of October ( my period started September 29th and ended on the 3rd of October and since then I had been going through some boyfriend drama and a relative being ill. Why I think it's PCOS is because well my period hasn't came since then but that's it I have no signs or symptoms of ever having it and it doesn't run in my family. So I just wondered if it was because of stress or could I actually have PCOS. Thanks.