The meter of this line isĀ iambic.
Iamb consists of an unstressed syllable followed by a stressed syllable. So here, I is unstressed, al- is stressed, most is unstressed, fell is stressed, a- is unstressed, and sleep is stressed.Ā
Trochee is quite the opposite, so that is incorrect, and anapest and dactyl refer to three syllables.Ā