I do not know why check-ins were stuck at the 24th, but there is a way to change them. In your "my goals" module is a link to "edit goals". On the edit page, change your check-in to Friday and save. This will allow you to check-in tomorrow. After your check-in, your date will be corrected.
If the date doesn't change immediately, sign out and sign back in or do a hard refresh (ctrl+F5) and you should see the change.