Hay, sa 18 weeks yan normal na kaya ng pregnancy hormones and the weight shift, pero if you're having trouble breathing along with it, best talaga na i-check mo agad with your OB kasi hindi dapat overlooked, a few of us sa mommy group namin nag-complain din ng ganitong combo and it turned out isa need lang ng proper posture correction, iba naman need ng follow-up. Siguro try muna gentle stretches at better pillow support para sa back, pero don't wait kung hindi sya bumaba, okay? Mas peace of mind both for you and baby