I think someone hacked my phone

So I accidentally clicked in an add and clicked ok and it just say that something was being added to my calendar I didn’t payed attention and just ignored minutes later my screen just went like black and green for like half a second like it does In those movies when a computer is being hacked then I went in to my calendar to check something and I saw that I had a lot of events so I checked one of them and it said that hackers were trying to get into my… I couldn’t read more it said that if I wanted to unsubscribe so I did but now I’m scared that they may steal my information or something. What can I do