Because "panic-stricken" is an adjective, it makes more sense the first way. Similar to the word "red," you wouldn't say "The car got red," you would say "the car was red." As the other answer mentions, you use "get" to refer to obtaining something. In your example, you might say "I got a ticket to fly to the USA." As you'll notice, in this example, you are retrieving a ticket. Thus, "got" is appropriate.
Realistically, anyone would understand you either way, of course, and it wouldn't surprise me to hear native speakers saying the latter, but the first one is correct.
Also, as a side note, in proper English you would say "...my trip to the USA," as compared to your "my trip to USA." I only bring that up since you said you wanted to get used to the language more. It's not a big deal, and it's certainly a confusing rule, but we refer to the United States, as I did just now, as "the United States," not just "United States." That is, of course, different from how we refer to "Canada" or most other countries.