Sounds very much like cylinder head gasket failure, and the fact you've been driving it like that for a while suggests the damage may be irreversible. Try taking it to a garage but be prepared for the bill to be more than it's worth.

It's very close to dying so don't go far in it or it'll leave you stranded.

It is a failing cylinder head gasket.

Head gasket.

Time to trade it in.

Now loosing power. :(

Some help would be great, the car drives fine, but is going through bottles of oil a month, there's no leak external, there's white smoke when rev'd, there's a misfire on cylinder 3 and the emission light is on all the time

Help would be great

Thanks Steven