“So, have you settled back into the routine?”
Your coworker had a baby and didn't work for a couple months. She returned to work three days ago. You are talking to her and making small talk. You ask her this.
So, have you settled back into the routine?
This is a good general conversation starter. It's often used right after engaging in a little small talk, to transition into more serious conversation. One of the purposes of using this word at the beginning is that it announces that you are going to bring up a topic but gives the listener time to prepare before you ask a question.
So, how have you been?
So, let's talk about what we need to do to prepare for this conference.
have you (done something)?
You use this when you expect something to happen to someone:
Everyone around here is getting sick. Have you caught it yet?
"Have you...?" is also better than "Did you...?" when you are asking for general news about a person's recent life:
Have you lost weight?
Have you seen "Avatar" yet?
Have you called your mother lately?
A "routine" is a way of acting and living that you do the same way, over and over again.
For example, your daily routine might include getting up at 8:00, ironing your clothes while watching TV, getting coffee at the local coffee shop on your way to work, etc.
To "settle into" a routine means to start to create a routine for yourself and to get used to it. For example:
Teaching is stressful at first, but after a few years you settle into the routine and it gets to be easier.
To "settle back into a routine" means to get used to it again after you stop doing it for a while.