Iv had gastric bypass and am 28 weeks pregnant. i had been having mild headaches but now its migraines and dizziness. what is going on?

Headaches: Your headaches could be coming from tension, dehydration, lack of sleep/poor sleep, skipping meals, stress, teeth grinding, sleep apnea/snoring, or chronic sinus problems among other things. See a doctor to get checked out so you can get som ehelp for your headaches.

Probably electrolyte: The bypass causes reduction of the ability to digest and assimilate food and can give nutritional deficiencies and electrolyte imbalance. Need medical eval and attention asap for yours and the baby's well being.