Hi prrrhapss,
If you haven't done so yet, restart your iPhone. Although simple, this step can help correct some unexpected issues. It's also a good idea to make sure your iPhone is running the latest iOS version, since this can help with overall performance: Update your iPhone or iPad
If an update is available, be sure to create a backup before installing it.
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
There are some additional steps that may be useful here: If the camera or flash on your iPhone, iPad, or iPod touch isn't working
Regards.