is my phone a spy device?

I am from India,

In our state Meghalaya there is a local Teer lottery game.

I am not interested in this kind of lotteries etc so I never searched about it.

yesterday one of my friend came to meet me and during general discussion he told me that his brother has won Teer Lottery etc.

At that time my phone was on table with active internet connection.

when my friend left. I start using my cell phone and when I open my facebook. I was surprised to see that there were Teer lottery ads everywhere on my FB wall.

I mean what is this? are they listing us everytime? We don’t have any privacy?

I have become tired.