When you entered the U.S., an electronic I-94 record was created for you. Have you checked it to make sure it’s accurate?
The I-94 is the primary determinant of how long you are allowed to remain legally in the U.S. All foreign nationals and their dependents should check their electronic I-94 information each time they enter the U.S. at: https://i94.cbp.dhs.gov/. International Scholars are encouraged to keep a printout of their new I-94 after every arrival in the U.S.
If your I-94 record has an end date that does not match your non-immigrant status, you should contact the OISS immediately.