So 4 days later and an update. 3 days ago, I put away all my 4mg juice, and started on strictly 0mg. That day went pretty good. I felt fine all day but something kept nagging at me in the back of my head.
Second day, still physically felt fine, but I felt like I was clenching my jaw throughout the day. It felt like I may have been going through slight nic withdrawal. I explained to my wife how I was feeling, and she went into my stash and brought me out a small bottle labeled 4mg. I filled up my carto with it and felt better about 10 minutes later. The rest of the day went smoothly, and I felt back to my old self.
Today, still using that 4mg labeled bottle, I noticed that I haven't felt icky. I figured that my thoughts of having a head cold might have been correct in causing me to feel that way a few days ago, and that it wasn't the nicotine. That is, until my wife asked me how I was doing... I told her that the 4mg really helped, and she then proceeded to tell me that she filled the bottle with the 0mg juice, and just wrote the 4mg label on it.
The withdrawal symptoms were completely IN MY HEAD! Once I thought I was getting nicotine, I felt ok, even though I wasn't getting any nic.
The reason I didn't immediately suspect that she gave me an incorrectly labeled bottle is because I order big bottles, but transfer it into smaller bottles for easier transport and less possible leakage. Having a 5ml bottle get crushed in my pocket is a lot better than a 30ml bottle getting crushed.