Girls, who has this or am I the only one... I was sitting with my child on…

Girls, who has this or am I the only one... I was sitting with my child on my hands, she was peacefully sleeping, while I watched videos on YouTube, and suddenly, out of nowhere, there was a feeling of anxiety, as if something bad was about to happen. My husband is at work, he only gets in touch on Mondays. Now I'm worried, is everything okay? It's scary that something will happen ?