I saw someone who was drugged and got kidnapped and I haven't told anybody
Why wouldn't you tell anyone about a kidnapping?
I'm afraid of others' opinions and their answers.
Feeling afraid and overwhelmed as you see a crime take place isn't uncommon. This sounds like it was a traumatizing moment for you. But make sure to tell the officials everything you remember now, no matter how much time has gone by.
I can't remember it anymore. I'm so scared if I tell them about the drugs.
I know that you are scared, that's understandable. But telling the police will help this kidnapped person and you really need to tell them.