How can I get my Android Market app back? I guess it somehow got deleted.
If your Android Market app somehow got deleted then you will just have to download another one yet again. You can log in to the www.appbrain.com/app/appbrain-app-market/com.appspot.swisscodemonkeys.apps and download the Market app.
They converted to Google Play (Play Google). Check your application buttons to make sure you don't have it (it's a white button with a sort of triangle in the middle) otherwise you'll have to download it again.
Reset your os android system.