@natashastano I'd start moving the contents across to a new phone. Seawater is particularly corrosive because of the salt content, so it's important to act quick to save your files.
Your documents and other files will either be stored on the phone storage or an SD card, so a broken SIM card won't affect those.
If you buy a new phone, you can still use an app like Samsung Smart Switch or other utilities provided by the phone manufacturer to move your data across.
You may need to order a new SIM card from your carrier to put into your new phone, but at least your data will be safe.