Im 34 weeks pregnant.i have gerd. i experienced weakness, dizziness, breathless, cannot concentrate when hungry or after eating, what is this?

Vitamin deficiencies: People with gerd, especially those taking antacids or Prilosec are prone to vitamin B12 and other deficiencies, which can cause the symptoms you describe. Blood test for vitamin B12 is not very reliable; if your level is less than 400 (rather than 200, which is what the labs say) you are probably deficient. Taking Prilosec also lowers magnesium level and can contribute to migraines migralex doc.