There are a couple of different ways you can quickly double-check if your stream is actually live to the public.
If streaming through the Sessions app
You can check if you're live by using another device to access the Sessions website - a link to your stream should be displayed on the main page if you're currently online, alongside other artists. You should also visit your own personal artist profile and see if there is a green "Enter Session" button there. See also: Help Article: "How can I find my artist public profile?".
If using Advanced Streaming
You can be sure you're live if you can see your video preview in both Preview Panes of your Advanced Artist Panel. If you can only see your video preview in the smaller Preview Pane to the left, you are not online to the public and need to click the blue "Go Live" button.