Hello menasor.
You didn't over-shoot your data allotment, did you.
Given that there are no issues with your data plan, I'm wondering if you've somehow changed the actual settings in the network/data section of the menu settings. Did you accidentally click to the "home" setting rather than "automatic" in system select? How about the data saver and data delivery check boxes? ..etc.
Have you tried clearing all data and cache in the internet apps such as the browser, then rebooting?