if your water pump is leaking it can't get into ur exhaust
how is your coolant level, has it gone down? does your overflow bottle have water bubbling out of it?
blue smoke = combusted oil (burnt oil usually compression rings)
white smoke = fresh non combusted oil (valve seals generally)
white smoke also = water
do a block check, local garage should be able to do this for you
also a compression check
white smoke on a cold morning can also be normal... condensation in the exhaust
keep an eye on it and let us know if it worsens