Uy, some tummy aches in first trimester ay normal talaga, mama, ang ligaments mo ay nag-stretch na at ang hormones mo ay all over the place, kaya yan ang common culprit! But since it's bothering you especially at night, better mention it to your OB just to be sure, lalo na if may bleeding or spotting, kasi mas peace of mind ka lang talaga. A few of us moms tried changing positions, like using a pregnancy pillow to support both sides or sleeping on your left, and it helped a lot with the discomfort, so try mo rin that!