tsure on "WordPress Dashboard Problems"

Ever since two weeks ago when the new wordpress came out, the functions in the dashboards do not work anymore. I am not sure why, please help me if you know how to solve it. Thank you in advance!

For example, for menu in the dashboard, when I click on the dropdown for posts, pages or others, it doesn't work and no dropdown is shown so I couldn't add new tabs to my website.

Moreover, when I create a new post or edit existing post, I couldn't type the tags or select from the old tags I had.

Things like these severely affected my ability to work on the website and update new information. Please help or tell me how to reverse back to the old version for wordpress since it might help solve the issue.

The website is http://www.swjoyoflife.com