Sounds like the Air con drain plugs are blocked . Mine did this during the Summer ( Ha Ha Ha HA ) with soaked drivers carpet for a bit. You need to get under the car and reach up into the gearbox tunnel and there should be 2 nozzles one on either side . There is a check valve in them and it gets blocked . The passenger side is harder to reach .Take them out of the nozzle and leave them out unless you are planning some wading. but keep em handy.