It means something like "suddenly really enthusiastic" or "suddenly very interested in".

What does it mean by I am sprung?

sprung (comparative more sprung, superlative most sprung) (slang, African-American Vernacular) Utterly infatuated with someone; completely taken over by romantic interest.

What is a Sprong?

a projecting piece that is used to lift or support or turn something. tand. something resembling the tooth of an animal.