I was a student for many years (5 years of undergrad, 2.5 years of grad school), and I became very comfortable with always being able to look at the syllabus and my grade and know what I needed to do and how well I was performing. Work isn’t like that. Like I think is normal, I get a performance review once a year. I find this unsettling, because even though I come in and do decent work, I still often feel like I’m doing something “wrong” and worry that I’m secretly on the cusp of being fired. Folks who have maybe been working for longer than I have, how do you feel and stay confident in your work?
Trust your manager and the people who hired you. They picked your for a reason. Sometimes it’s not what you think makes a good employee in this position, but something much more specific to the team or situation you’re in. If in doubt: Ask!
Many times people who come straight from uni don’t feel productive enough, because they can’t be productive for 8 hours straight. But that’s normal. Staring at the ceiling blankly on occasion is normal too. If you’re doing your best and the matter you’re working with is working well for you, then you’re very likely fine.
There’s always a bit of impostor syndrome in all of us, but still try to get comfortable and trust your colleagues. Ask for feedback from your superior, if you’re unsure.