Oo, normal lang yan sa pregnancy, especially ngayon ka na 31 weeks, marami sa amin na nag-experience ng headaches dahil sa hormones, dehydration, at stress kaya huwag mag-alala. A few of my mum friends swore na ginawa nila mas lighter ang caffeine intake at nag-drink ng maraming tubig, tapos bumuti na agad, pero if it's really persistent o severe na, better mag-check ka with your OB para sure lang, okay? Mine usually went away after I delivered, but everybody's different talaga.