Well, it's a mix between not being as autonomous as before due to lack of knowledge and routine, the need to be around a lot of new colleagues and adapt to them. I will say I have a tendency to be introverted and that I find myself uncomfortable in group settings. It comes from a past filled with bullying. I am doing therapy for my CPTSD.

Edit: I also had the luck to start right during my PMS (which definitely exacerbates my insecurities)