Some great advice I got in preparing for grad school involved a small writing activity on my reasons for choosing to go to grad school, the program I picked, and my advisor. This brief reflection is useful for evaluating those inevitable feelings of doubt in my choices. It could be a specific stressor making me anxious and spilling over into questioning those choices or it could be a serious concern that needs to be addressed.
This can be particularly useful for anyone considering leaving a given program, lab, etc. You can see how your experiences after being in the thick of things compare to your expectations from the start. You can also assess if your personal and/or career objectives have changed and thus changing what you now need out of your graduate school career. Or reassure yourself that while X things are stressful or unpleasant that you are still getting enough benefit to make overcoming them worth while.
Grad school is a long process so it’s reasonable for your interests and goals to be remolded as you move through the program. So taking the time to re-evaluate your planned trajectory and if grad school is still supporting you in getting there. And if it’s not, decide what needs to change to get you there.