16 weeks very lightheaded!!

So I’m at work and I am feeling so lightheaded! My shift is 6am-3pm, but ive been awake since 3:30 this morning! I have to be on my feet basically all day but I am feelings so lightheaded I can barely stand! I don’t know what to do I’ve never been this way and now suddenly at 16 weeks? Is this normal? Not sure what I should do. I’m worried I’ll get in trouble for taking breaks to sit!