How bad is my sinusitis/bronchitis going to get?

Looks like you got yourself a good infection. You're on the right track with that nasal saline rinse. It'll help keep the infection at bay till you can seek some antibiotics to help fight it off. About the thin orange discharge... Sounds like blood with thinned out infectious substance. And the bronchitis, that's going to be a little bit harder to cure. You may want to try using a humidifier at night while you are waiting for your appointment.