This is very normal. It’s a guilt reaction. When we get a thought we tend to over analyze and ruminate on the thought. The more we do this the more the brain tells us we are in danger and we are constantly in fight or flight mode. Our anxiety is overly heightened and with that comes an inflated sense of danger. Once the anxiety is lowered we can see things more rationally. Try and delay the rumination as much as possible by living parallel with the fear yet going about your day as of nothing is wrong. You will eventually show your brain there is nothing to fear.