Apparently there's a career-path consultation today. So it's just me and Pam today.
Literal
Career-path-consultation [subject-が] exists-[explanatory-んだ][hearsay-って][final-さ]. So today [topic-は] me [and-と] Pam [only-だけ] is-[copula-だ].
Casual school speech. 進路相談 ('career-path consultation') is a regular feature of Japanese secondary education — teachers meet with students one-on-one about their future. ~んだってさ stacks three casual markers: んだ (explanatory) + って (hearsay) + さ (masculine assertive/informal ender). The whole cluster means 'apparently, I hear that X, you know.' 俺 is casual masculine first-person.