It should get better...
It's important to realise that 'morning sickness' can occur at any time of the day, although early morning is a common time. It's not unusual for a woman in early pregnancy to wake up feeling sick.
Feeling ill can start before you miss your first period, but it tends to get better over time and it's typical to feel much better after three months. Not everyone is so lucky, however: a very small number experience it throughout pregnancy.
It's believed that pregnancy hormones cause the sickness. These circulate in the body, affecting all your organs and preparing your body to sustain new life. One of the effects is nausea. While it's a nuisance, and at worst a severely uncomfortable condition that can lead to undernourishment and constant tiredness and weakness, there could be a good reason for it to happen.
Is Mother Nature intervening?
One theory is that your body's protecting the foetus from harmful substances. Women who suffer bad sickness, including vomiting, are less likely to miscarry, and the sickness generally stops when the growing baby's major organs have developed.
Another theory is that the body's 'starving' the mother, so more nutrients go into the development of the placenta, giving the baby a better chance of being well-nourished later on.