Hi, I have a few ideas which might work, might not.
It appears that you have customized things, as my taskbar isn't that small. I also have the date below my time. If you are using an older version of Windows, try Windows Update. If it is customized, undo the customization and maybe that will help.
Idea 1: Go in and choose a different theme.
Right click desktop, Personalize. Themes. Theme Settings. Choose a different one, then back to your normal one.
Idea 2: Classic Shell settings.
Do you have classic shell installed? If so, go into the settings and taskbar tab. Try making a minor change or two and choose OK. This could causes the font to reset.
Idea 3: Open Control Panel. Open Date and Time. Click the Change Date and Time button. Click Change calendar settings. This apparently opens 2 dialogs at once. Click on the Time tab. Make sure the Time Format is correct and you see a semicolon. You could choose the Reset button at the bottom, but I'm not sure what it will and I'm not going to test it on my system.
https://www.howtogeek.com/wp-content/uploads/2016/03/18_time_tab.png
If none of those help, reply back.