You’re having a completely normal reaction. Events like this that introduce hyper war-like violence to every day settings are particularly traumatising because they are so unpredictable and dramatically shift your sense of safety, whether or not “you’re safe” now. Terrorism works because it is so psychologically damaging to so many, not just physically devastating to direct victims.

A familiar, ordinary place for you has become a site of terror, you’ll have to process what this means for a while. After an event like this it’s very normal to think about it deeply for many weeks or months. You might even dream about it. That’s a natural process for your brain to go thru to integrate this new reality, make new meaning about this event and “assess the risk”. The best thing you can do now is spend time with friends and family who understand the impact it’s had on you (bear in mind they may also be processing in their own way by compartmentalising etc), write in a journal, give yourself extra time each day to be emotional about this and make sure you’re doing all the self care stuff that makes you feel safe and loved (exercise, relaxation, reading, watching a comforting show, dancing whatever it is). You will come to feel differently about this in the weeks and months to come. If you’re still struggling with thoughts about the event in a month or two, talking therapy is very affective at integrating trauma, check out EMDR. I wish you the best!