A new beginning at work is easier when you stop demanding that familiarity arrive on the first day.

Competence in a new place is mostly local knowledge, and local knowledge takes time rather than effort. The first weeks feel bad partly because you are comparing yourself to how fluent you were in the job you left, which took years to build and is not a fair standard. Feeling slow is accurate information about how new you are, not about how capable you are.

Give yourself a horizon of a few months rather than a few days, and write down what you learn each week. Ask the questions early while asking is expected. Fluency arrives on its own once you have enough ordinary days behind you.