Ay nako, mama, ang palpitations at nervousness during pregnancy can happen talaga, pero please have it checked by your doctor as soon as you can, hindi dapat i-ignore ito, especially since you're already 13 weeks. Better safe than sorry, 'no? A few of us mums experienced something similar and it turned out okay naman, pero kailangan talaga ng proper check-up para ma-rule out kung anong dahilan at ma-ease your mind. Huwag mag-alala, ang doctors namin nandito lang to help, call your OB today if pwede na, or go to the nearest clinic. You and baby need to be checked. Take care, mama!