Eh, normal la tu at 15 weeks! A few of my mum friends had the same thing, some say it's the hormones playing havoc, some think it's because they're not eating enough or blood sugar drop selepas makan. Tapi kalau it's happening consistently, better check with your doc just to make sure everything's okay, boleh? Tak ada yang nak risau-risau unnecessarily kan, especially first baby. Try makan smaller meals more frequently instead of big meals, and make sure you're drinking enough water, sometimes that helps!