Relax. Step back from this. Wait to see what happens.
In the meantime take care of things for yourself. Citizenship is important but there is nothing critical about it for a PR who is an American citizen.
Start focusing on taking care of your day-to-day stuff.
You should have known what you were signing. If, for example, you were signing something that is not correct, that could be a crime. That is true in any meeting with any government official. Slow down some and focus. Pay attention to what you are doing.
As I have mentioned elsewhere, the not updating your drivers' license for years: not good dude. Not good. Done, OK, work with how things are now. Get the new job if that is what you need. Citizenship can wait. Get the details in your life in order: update the drivers' license to where you actually live.
Some forum members have advised various ways to work around the mailing of notices issue if you move. Forget that. Just do the right thing for you and if you move, give CIC the information soon, and then check to make sure CIC has your correct address. Many people could probably do things one or the other way suggested. It looks like you would be better off just getting things in order. Follow the instructions. Read things before you sign them. If you do not understand, ask. Take a breath, relax, and focus on doing things right.
As for what you signed: the main thing it was about is that you have not been charged with any crimes, not on probation, no criminal convictions, and your PR status is not subject to any inadmissibility reports. If there have been no criminal charges in the last four years, or the four years before you applied, then you are OK. Not a problem.
No need to be embarrassed. Again, step back, relax. You are probably just in wait mode now. How it will go is how it will go. Nothing you can change at the moment. In the meantime, take care of you, of your needs, do what you need to do to get things settled in your life.