Stolen Phone

If you don't have Find My turned on and you don't have theft and loss protection.. then you will not be able to locate the phone and you would be at a complete loss

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

When find my is turned off, you cannot find or remotely erase your device

What you can do are some steps in order to keep your data as safe as possible

1. Change your Apple ID password
2. Change your social media accounts that are on the phone, passwords
3. Contact your carrier to get your SIM card blocked