I didn't eat enough today and I've been dizzy. What do I do?

I've probably only had about 1,100 calories. Ate breakfast and dinner and sort of snacked on cereal and fruit in between. But I've kind of been laying around all day too. It freaks me out to feel dizzy. I usually consume 1,400 and work out. Not sure what to do, don't have much food in the house. I don't feel awful just when I stand I feel dizzy until I move more. I'll be eating much better starting tomorrow. Just sort of felt like I ate bad for Xmas and was trying to eat very lightly this weekend... I think I've made a mistake. I'm worried. I'm 5'2", just under 100 pounds and in my late 20's.