Ay hindi normal yan, mama, nahihilo after kumain at maligo sounds like it could be low blood pressure or dehydration, especially if first trimester ka pa o postpartum. I'd really suggest checking with your OB agad kasi importante na kumakain ng maayos ka for baby, and they can check kung anong cause at bigyan ka ng proper advice. One of my mum friends experienced something similar and nag-suggest sa kanya ang doc na mag-eat ng smaller meals more frequently, plus drink lots of water throughout the day, pero kailangan talaga ng doctor's check-up muna para sure! Take care of yourself, mama.