QUICK ANSWER
"Te extrañé" is a form of "te extrañé", a phrase which is often translated as "I missed you". "Extrañaba" is a form of "extrañar", a transitive verb which is often translated as "to miss". Learn more about the difference between "te extrañé" and "extrañaba" below.
te extrañé
A phrase is a group of words commonly used together (e.g., once upon a time).
1. (informal) (second person singular)
A word or phrase used to refer to the second person informal “tú” by their conjugation or implied context (e.g., How are you?).
extrañar(
ehks
-
trah
-
nyahr
)A transitive verb is a verb that requires a direct object (e.g., I bought a book.).
a. to miss
Extraño mucho a mi familia cuando estoy de viaje.I miss my family a lot when I'm traveling.
2. (to amaze)
a. to surprise
Me extraña que no haya venido a trabajar.It surprises me that she didn't come to work.
extrañarse
A pronominal verb always uses a reflexive pronoun. (e.g., Te ves cansado.).
a. to be surprised
Me extrañé de que no se acordara de mi cumpleaños.I was surprised that she didn't remember my birthday.