Sorry to hear about your issue :(
Even if your iphone is in silent, you could be able to play sound on it through icloud.
Sign in to icloud and click on "find my iphone". It will locate your iphone. Once located, click on it and then click on the "i" icon next to it. It will give a new window where you will be able to "play sound".
Let me know whether that helps in finding your iphone.