Ay, low blood sugar talaga yan at that's why you're getting dizzy spells, happened sa isang kaibigan ko rin around that stage ng pregnancy, grabe ang feeling! You really should check with your OB agad kasi 24 weeks is important, at sila lang can properly advise kung kailangan mo ng special diet or if may underlying thing going on. In the meantime, a few of us who had similar episodes tried eating small frequent meals with protein and complex carbs (like peanut butter on whole wheat, or egg with rice) instead of long gaps between eating, kasi the blood sugar dips are no joke talaga pag pregnant. But seriously, don't self-diagnose lang, your doc needs to see your full picture to make sure baby and you are okay. Take care and update us, ha!