、、。
It seems what I just saw wasn't an act — that was her real self.
Literal
Apparently, just-now [gen-の-topic-は] acting [copula-ではなく], real-self [copula-だった] [seems-らしい].
さっき 'just now' + の forms a nominalized 'the one (thing/person) just now.' ~ではなく 'not X but...' uses the formal conjunctive negation で (copula) + はなく (negated ある) + [new option]. The key vocabulary is 素 (す) 'one's real, unadorned, sober self' — a concise single-morpheme word where English needs a phrase. どうやら...らしい again stacks inferentials.