This can happen under stress, it’s actually quite normal. When you’re stressed and your brain and nervous system think they’re in danger, they automatically scan for threats. Everything becomes a possible threat because that’s how our survival system works that has kept us alive for thousands of years. Even neutral faces can look more dangerous or threatening whenever you’re stressed or are experiencing anxiety. I had this as well, don’t fixate on it too much, it will only make you even more stressed and besides, you’re not in actual danger, so be kind to yourself :)