I am a software engineer, and some items are always roaming in my brain about the work I am doing like

1. send an email for this user story
2. I may not have correctly understood this requirement
3. I would have done that; differently; I will make this change tomorrow.
4. I have to complete this by tomorrow.

Hence, I am not even getting the sleep and cannot adequately prepare for my future.

Is it common for everyone who is working on busy projects? How do we avoid those? Do I need to maintain some scheduler?