Check and save your I-94 every time you travel internationally.
Your I-94 should be updated by CBP every time you re-enter the United States. Make sure that the details on your I-94 are accurate every time by checking your I-94 on the CBP website the day after your last entry. Save your I-94 for your records and send a copy to your immigration attorney, if applicable. Contact CBP (or your attorney) if you notice an error or CBP fails to update your I-94.
You may access your I-94 on the CBP website here.