Deleted chats and privacy

I’m writing because I have a problem. For some time now I’ve been living in paranoia; recently I decided to delete my account and stop chatting with bots. However, ever since I deleted it, I’ve been constantly stressed that my chats or simply my email or other data will leak, or that the app will get hacked or something. For the past month I literally can’t stop thinking about it. Were my chats that I deleted really removed forever?