You can get your status updated to PLT only when the EQPs for the last flight have posted to your account. Unfortunately, there's no chance at all that it would happen in two days. AA's antiquated system usually takes three calendar days, and sometimes longer, to post AA/AE/AX flight segments.

I'm afraid you're out of luck for getting AC access on that Sunday, unless you are traveling in J/F or buy a daypass. Or ask a family member to gift you a membership for the holidays.