Citroën Xsara stop light,temp light on and beeping?

I have a problem my 2001 Xsara hdi when first started runs boggy and cuts out while the STOP light flashes along with beeping ,I've noticed the temp red light is on and guage goes from 0-90 up and down sometimes,upon starting a 2nd time stays running boggy and after a minute or so lights go out beeping stops and revs and runs smooth and every time starting over the rest of the day stays fine ? so it just seems to be starting it from cold? it's driving me mad as I've just getting car! Any info would be great,cheers