I recently switched cable service. Now I can no longer use my apple tv to watch my own videos on my apple tv?

Home Sharing is not influenced by your cable service. Your home network would be independent of your cable service. If your cable service supplied the modem-router, then a new provider may be reason to set up the home network again.

Use Home Sharing to share media from a computer to other devices - Apple Support

What is your model Apple TV? Identify your Apple TV model - Apple Support

Please try the following:

1. Unplug your modem from its power source and Restart Modem.
2. Unplug your router from its power source and Restart router.

3.Unplug Apple TV from Power for 2-3 minutes – re-plug in and retest.