I had that a few weeks back. The midwife suggested eating some of those yoghurts with all the live stuff in them, like Activia.
I get really dizzy when i am hungry... although i dont realise im hungry all the time becuase my baby tends to push itself up into my stomach!
Dizziness or feeling faint is a normal symptom during pregnancy. The main cause of dizziness in pregnancy is due to the rising hormones that cause your blood vessels to relax and widen. Dizziness is also caused by low blood sugar levels that may occur as your body adapts to changes in your metabolism. Women who are anemic or who have varicose veins may be more susceptible to dizziness than others. Dizziness may also occur later in your pregnancy if you lie on your back, allowing the weight of the baby to press on your vena cava (a large vein that carries blood from your lower body to your heart).
I had this and tried everything, but nothing seemed to really help. I mentioned it to my midwife and she did some blood tests just to check things over, and turned out my iron levels were really low. I'm now on iron pills until bubba arrives and feeling much better.
Hope this helps