Welcome aboard, @Oona
First off, you are doing a truly great thing by quitting smoking. I cannot give you advice on Chantix as I did not quit that way but there are a number of people here on this site who did quit successfully with Chantix. I am sure they can give you much better insight about it. Regardless, you are doing a great thing in quitting, regardless of method.
This is definitely a safe place to vent. Feel free to post about anything you are struggling with. Post all you want. We have all gone through what you are experiencing and yes, quittin