If it did well for 18 months, then you can't have been doing much
wrong. Did you start doing anything any different? If not, then
maybe it could do with some fresh 'soil', unless some sort of pest
is getting at it. Is it getting enough light? They don't usually
grow traps in Winter.
For 'soil' use straight peat (some people seem to call this peat
moss), or sphagnum moss. Include some lime-free sand if you like.
Do not use proprietary potting composts which will include plant
food, or lime. Keep the plant stood in rain water or similar, and
do not apply any plant food.
-- Clarke Brunt (clarke@brunt.demon.co.uk)