3rd Time Mom

Twins run on husbands mom & dads side. His mom has twin sisters, his dad has twins in the grandmothers generation and husbands generation. I feel like Im showing super early and gaining more weight than I like. I dont have an ultrasojnd until im 8weeks 2 days along. Im 6 weeks 2 days now so 2 more weeks and the wait is killing me. My normal weight is anywhere between 114lbs and 130lbs I usually sit at 120. Im 150lbs 8 months pp got down to 145 10 months pp. Within the last 6 weeks Ive gotten up to 156lbs. Ive been eating much better so Im confused. Nausea set in 5 days ago but isnt as severe as my last 2 pregnancies. My first I didnt show until 6-7 months. Like not showing at all until then. My second I showed at 3-4 months but looked like I do now just pretty bloated small bump. I stayed so small my whole pregnancy no one ever believed I was as far as I was. Im now showing like I did at 3 months with my last one. Ive also gained like 6-10 lbs which seems crazy to me. Is it because its my 3rd? Is it because Im only 11 months pp and breastfeeding? Could it be twins? HCG was 145.7 at 4 weeks 2 days.