I think a big difference is what the free time is like. I worked full time or nearly through college, so I didn’t have much free time in terms of quantity. When I got it, it was often with friends and during the day. When I graduated, I got a job with regular hours for the first time- I had so much free time, but I didn’t have a lot to fill it with, nor did I have a lot of energy after sitting down. Developing an active hobby helped with both, but doesn’t work for everyone.
I’m in grad school now, working 30 hours a week, and I do feel much more weighed down, but I’m able to set my own schedule a lot more than I could when I worked in an office