@ LillyC
Assumption: No deal Brexit
First day, probably not much (kids go to school, birds fly, the normal stuff) - 30th March is a Saturday. The normal stuff happens, except that when people go to Tesco's, they'll fond the shelves looking bare, as people will have been stocking up since the beginning of March, if not before.
First few days, trucks getting stuck at the border controls with our food and all other goods we import, with that inflation will peak Everything else normal There will be few trucks stuck at the border, as UK and EU hauliers will begin calling their trucks home from around the 20th March so as not to have their vehicles and drivers stranded on the wrong side of the Channel on 29th March. Same will apply to planes and ferries. food supplies will not just be delayed, they might not get through at all. Neither will raw materials and components, meaning that factories will go to short-time working or close. Unless there is some kind of rationing, food prices will rise rapidly, as will fuel prices. Nothing will be normal if panic sets in.
First week food shortages in our supermarkets - first week and for months afterwards - see above re trucks and planes.
businesses shutting down their operations in UK to move elsewhere in Europe - this is already happening (Easyjet to Austria, JLR to Slovakia, NIssan and Japanese CEOs stating that they will not stay in the UK if they cannot make a profit) and will increase in pace by Christmas if No Deal looks likely
First few months europeans packing their bags to move where the money goes and with that taking the capital and know-how with them and more companies moving out Again, this is already happening and has been throughout 2018.
No major panic, life goes on - Life, Jim, but not as we know it. I'm guessing that the panic will set in when people discover that there are food and medicine shortages, that they cannot afford what little food is available, that the NHS is for emergencies only, that the care homes have closed and they are forced to look after their elderly relatives themselves, that they cannot get to work because of the fuel shortages, that their jobs are on the line as the UK goes into deep recession.