There are some threads here about Emgality. Put it in the search bar (top right of the page) and you'll see them. Emgality is only expected to work for people with episodic CH, not chronic, but from your description, you might not meet the specific definition of chronic.
It's not likely that O2 ended your cycle. Doesn't really do that (but since CH is pretty different for everyone, I wouldn't state that as a certainty).
Check out the D3 regimen; it has helped hundreds: http://www.vitamindwiki.com/tiki-download_wiki_attachment.php?attId=7708