Who were all the people who heard your engagement announcement? Is there actually someone who you have been seeing that they know? What did they say? Did they believe you?

Being depressed and overdosing is the bigger problem and it may be that no one even paid attention to your "announcement" if it was not formal or there is no other person they know. It might just have been seen as something odd you said when you were drugged.

I would ignore what you said until someone asks about it and then shrug and explain you don't know why you said that, it isn't true. But I would work on the depression and immediate problem with overdosing more.