Twitch rolled out a new backend for their video system last week. One side effect is a 30-60 second lag, so when you start your broadcast, video might not show up on Twitch for 60 seconds. So maybe wait for a little while after you start broadcasting and see if it shows up.
Twitch is working on fixing this, which I hope they do because it makes it very hard to talk to your chat when they're 60 seconds behind you.
