Last year, on the way home from a French holiday, we had a 2 hour wait at Calais. There were 5 men (20s and 30s) in the car parallel to us. I watched them pace around, check their phones repeatedly, hardly speak to one another, take selfies with the ferry in the background. They looked a bit wired.
By the time it came to board, I was close to a panick attack. I had emptied large water bottles and put them in my Beach bag, with a pashmina, and I had worked out how best to tie them to DD's body if we were to end up in the water. I saw the port police circling the rows of cars and was convinced that the car next to us was being watched.
Fear is so powerful. I felt daft afterwards, but for those few hours I was utterly terrified.
That's not making terrorism 'about you', it's reacting to fear.
The thing is, this is why terrorists do these things... to drive fear into the minds of ordinary people... to stop them living with joy.
What you're feeling is a natural fear response, OP, but you have to be better than the terrorists, or they've beaten you. Be strong, go on holiday and live with joy.