It's Not Just You: Gmail Is Slow. Google is experiencing a glitch with Gmail that's causing the web mail service to slow down for some users. To fix the problem, you can go to your Gmail settings (the gear icon in the top right of the screen) and click on "Hide the People Widget," then save and also there is following Troubleshooting steps regarding Is Gmail Down.
• Update your Gmail app. To get the latest fixes on problems with sending or receiving mail, update your Gmail app.
• Restart your device.
• Check your settings.
• Clear your storage.
• Check your password.
• Clear your Gmail information.

And also contact if there is any problem which you cannot solve it. Then pleases contact to
Is Gmail Down. We can resolve the entire problem with a minute.
https://www.techjaadu.com/blog/why-is-gmail-down/