I am currently taking ambein for insomnia.but every morning whe i wake up i am tiredd the whole dy and it feels like truck hit me with a headache ?

Ambien (zolpidem) hangover?: One possible reason for this is the Ambien (zolpidem) is giving you a "hangover" because it is too strong or too high of a dose. Another is that the Ambien (zolpidem) is not doing it but your poor sleep alone is making you feel this way. Best to check with your doctor. Of course, finding the reason for the insomnia is important! if not due to the ambien, (zolpidem) you might benefit from a sleep study.

Every body different: Every body metabolism is different. Most will metabolize this drug in 8 hours but some it may be 4 and others it may be 12. Lower dose can be helpful but also make sure you don't have an actual sleep disorder that is being missed (like apnea) because medications like Ambien (zolpidem) worsen apnea so now apneas are longer and lower oxygen and you wake up feeling worse than when you go to bed.