I’m starting my new full-time office job in a few weeks after working part-time for a few years, and I want to make my rough adjustment as smooth as possible. How can I make my working more mentally and physically comfortable?

When I turned 18, I worked full time at a local store near where I lived. It was mostly a standing job and I adjusted to the schedule quite well. I had to leave about 8 months after though due to moving a bit too far to commute without a driver's license.

After that, I could only find part time positions, and as such have been working part time for around the past 3 1/2 - 4 years now. The stars aligned last week and I found a full time front desk receptionist job near me that offered me the position.

While most the days are 8 hour shifts, Sunday is 6 hours (fine with me), but at the cost of Monday being a whopping 11 hours (or 10, granted I get an hour long break that day). Considering i'd likely be starting on a Sunday or Monday even i've been quite intimidated.

My body adjusts to schedule changes slower, so I fear by the 4 hour mark I might become jittery or anxious, being used to leaving work and going home, especially on the long day. I've been told this is normal, but I'm still scared.

I don't want my fears to affect my mental state as strongly as it inevitably will on my first days, and I heard that many things office job people do to make their working more physically and mentally comfortable, and would love to hear how people adjusted or made their working more calming, in hopes it might help me. Please, tell me what's worked for you.