smoke and bog

After about 10 minutes of driving, my cars idle will drop from 1000 to about 200 and cause me to bog as if i had cams. I woud always have white smoke come out right after this occurs. I already changed my oil and spark plugs. I tend to lose coolant ONLY AFTER DRIVING! i havent drove my car for one week and the coolant remained so no leaks and water pump is still good. No mixture of any kind on my coolant or oil. What could this problem be?

i might be off here, but… aren’t those all signs of a head or head gasket problem?

i’ve thought it may be the head gasket but no mixture on coolant or oil. is it possible to not have any mixture on them and have a bad head gasket or it must be mixing with something?