Like a classical panic attack, feeling that i have to throw up, shivers, sweating, super bad anxiety, high pulse, fear and i always want to 'escape' to somewhere safe. I wouldnt call them flashbacks and judging from your experience it sounds like a panic attack, nothing to worry about and keep in mind that it is a fully natural phenomena, it just occurs at the wrong time instead of when it should, like when you are being chased by a lion. It's an ancient reaction that has kept humanity alive for millenias.