[wrholt]

I did a search on wordreference.com for English-to-Spanish translations of "panic". A couple of other possibilities for your first four sentence could be "sentir pánico" or "aterrorizarse". That is:

I panicked = Sentí pánico or me aterroricé

I was panicking = (yo) sentía pánico, (yo) estaba sintiendo pánico, (yo) me aterrorizaba, (yo) me estaba aterrorizando, or (yo) estaba aterrorizándome

She panicked = (ella) sintió pánico or (ella) se aterrorizó

She was panicking = (ella) sentía pánico, (ella) estaba sintiendo pánico, (ella) se aterrorizaba, (yo) se estaba aterrorizando, or (ella) estaba aterrorizándose

Note that in the imperfect the first-person singular and third-person singular verb forms are identical; often the context makes the intended subject of the verb clear, and sometimes the context it unclear and one needs explicitly state the subject in some manner.

Your last sentence is different: the suggestions for "panic-stricken" include:

asustado/a
muerto/a de miedo
en pánico

Also, in addition to "aterrorizarse" = to panic (intransitive), there is also "aterrorizarle a alguien" = to panic someone (that is, cause someone other than the subject to panic). For example:

(yo) le aterrorizaba (a ella) = I was panicking her or I was causing her to panic
ella me aterrorizaba (a mí) = she was panicking me or she was causing me to panic