I just started the Nuvaring 3 weeks ago. I'll be taking out my first one tomorrow and inserting a new one right away. I think I've used it correctly so far. I inserted it on the first day of my period, and even waited an additional 7 days just to be sure it had kicked in before having sex without another form of protection.
Since starting, I've had alot of nausea, diarrhea, dark brown discharge, some cramping, and extreme mood changes.