I'm thinking of overdosing so I can be with my dad
Are you doing this because of family problems?
Yeah, I really wish to be with him since he died last summer.
You sound like your going through a rough time. Your dad would be sad that you committed suicide instead of confronting your problems constructively. May you consider counseling to talk through this.
It's only been a year and a half.
Suicide is not something that is going to solve your problems. There is a reason to want to continue living, and you committing suicide will only bring more pain to your family. Talking about these emotions you are feeling would be the best way for you to feel better, so seeking a therapist or counselor would be a huge step!