Thanks for the query.
Some amount of fatigue
is common in pregnancy
But as you are having severe problem better to look into following things:
-In case of hyperemesis gravidarum
extreme fatigue etc. are possible. So if you are having excessive vomitings etc. take sufficient fluid replacement.
-Check for your blood pressure and blood sugar levels.
profile once to rule out any abnormal values.
With this primary workup, possibly the cause for your problem can be identified and treated.