I am only 8 weeks, but this is my 3rd time at it so I do have a bit experience with pregnancy. Your weight can jump around, just like it does when you aren't pregnant. Did you eat anything salty yesterday? Could be you are retaining water. You said you are feeling constipated. Sorry for the description ladies, but I was constipated this week. Didn't go for 4 days. Finally went and lost 3 lbs! Yes that could be part of it! Don't feel discouraged. You probably really didn't gain 8 lbs. You probably did gain some. Have to admit that. But, gaining 3 or 4 lbs in 20 weeks is amazing! Don't eat light and starve your baby. That is not good. Plus, if you eat too light, you might end up getting light headed and fall and do some damage. I am known to faignt pregnant. Especially if I get too hungry. I collapsed last week. Not good. Good job on the weight loss before the pregnancy. I lost 40 lbs before I got pregnant. Freaking out over the weight gain. Like I said I am only 8 weeks and have had some extreme naseau. But, have lost 8 lbs since I found out. I don't think gaining nothing is a realistic goal for me. But, I do have a goal of only 10 this time. As far as tips to not gain extreme amounts. Just eat healthy and exercise. I gained an extreme amount of 65 lbs my first pregnancy. Didn't work out and baby (or me) ate ice cream and regular ranch dressing regularly. Couldn't get enough of either. 2nd pregnancy I did better. Chose healthier choices and worked out until I was about 30 weeks when I was told I couldn't anymore. I gained 27 in the end. Most at the end there. This time I am doing even better. I have a goal (1st trimester) of 1500 calories a day. Haven't been meeting it half the time but am close. Plan on upping it by 200 calories 2nd trimester and another 200 3rd. But, if my stomach calls for more food I will eat more. Just ate a low fat yogurt minutes ago because I was starving before my lunch time.

Sorry about the novel. Hope that helps. Good luck with the rest of your pregnancy.

I'm on my third pregnancy, and with this one as the ones before I have severe hypermesis, a picc line in my arm, and lost 15 pounds in the first month. I am trying to gain weight, at 24.5 weeks I am not even showing. I am jealous of you ladies that can have control over what/when you eat! That being said, absolutely constipation can account for a pound or two or three. Don't stress, let your body do it's thing, you will work off any extra when it's all over!