Here's a corrected version with explanations:
"Yo estaba pensando en ti antes hoy"
* "Yo estaba pensando" means "I was thinking" in the imperfect tense, indicating an ongoing action in the past.
* "en ti" means "about you" and is the preposition "en" followed by the object pronoun "ti" (you).
* "antes hoy" means "earlier today" and is a less common way of saying "this morning" or "earlier today." It would be more common to say "esta mañana" or "antes de hoy".
So, the corrected phrase means "I was thinking about you earlier today."
Other possible corrections:
* "Yo estaba pensando en ti antes de hoy" (I was thinking about you earlier today.)
* "Yo pensaba en ti esta mañana" (I was thinking about you this morning.)
Let me know if you have any other Spanish phrases you'd like to translate!