Horrible dizzy spells?

ash

I’m 16 weeks today & I’ve been having awful dizzy spells😭 I can be perfectly energized and all the sudden I have to sit down and stop everything I’m doing bc I get so light headed & I feel extremely tired all of the sudden & fall asleep for hours sometimes without really deciding to go to sleep, should I be concerned?

(Not dehydration I drink a gallon of water every day)