Congrats on quitting!
You will most likely get a few more positive tests. Just tell your doc that you used to be a daily smoker, I'm sure they have seen it before
Yes I smoked everyday before I found out about baby
You must have been smoking regularly for a long time. In that case it can stay in your system for up to 4 months.
A friend of mine smoked a hell of a lot, he stopped 2 or 3 before a drug test at an important internship, he failed the test and was fired.