can't stop thinking about 'people'

Have you ever had this problem -

You see someone you recognise but you don't 'know' them - it could be some customer or

someone you saw somewhere

It happened to me when I went to the markets and I was walking along - someone bumped into me

after I bought something - only slight bump then one second later when I turned around I saw

some old person that I recognised but don't 'know' - I kept walking

She didn't see me anyway she's too short I saw her eyes were looking somewhere else or that's what I reckon

the problem is after I keep thinking about it and I don't know why

I keep getting 'flashbacks' that I don't want from work - too many customers I reckon it's messed

up my brain

anyone have something similar?