Time is not accurate/time is lagging

For the past few weeks, the in-game time is not lining up with my schedule. For example, my sim starts class (or work/school/or any activity) at 8am, it’s 8am and I won’t even get a notification stating “Alina’s class (or work/school/any activity) starts in about an hour” till 2 (in-game) hours later! Then 3 (in-game) hours later, she’ll go off to the activity. Another example is my sim needed to do a presentation for university which is from 8am-4pm. I waited till 8am on the dot and the option to present I wasn’t available because the time was too early but… it wasn’t! It was 8am.