"What was rough with the pregnancy was just the terror of the weight gain," the Grey's Anatomy alum says during an interview with PEOPLE. "You're going to gain weight — that's just part of the whole thing. Stepping on that scale every month in the doctor's office was heartbreaking for me because I'm used to watching that so closely, and the moment I start putting on weight being like, 'Oh no, I have to rein it back in.' "
She continued, "I tried to be as healthy as I could about it and not go crazy and go over the top with weight gain, but I still gained a lot for me."
The actress said she gained 40 pounds while pregnant with her little one. "That's hard for an actress who's spent her whole life trying to always lose that last 10. But I'm so grateful for my body right now because I feel like it's doing what it needs to do."
Breastfeeding is a completely different story — that brought a whole slew of different physical changes to her body.
"My boobs just got so ginormous," she revealed. "It was horrifying! I've always had fairly large breasts, but [I went from a] DD to an I. Did you know that an I even existed in bra sizes? I didn't. I didn't know that until I started having to buy bra sizes in an I. That's D, E, F, G, H, I — that's horrifying!"
While she may have huge boobs to deal with now, she attributes breastfeeding to helping her losing the baby weight.
"Within a week and a half after he was born, I dropped so much weight, and I was like, 'Oh my God, my body really does know what it's doing, I'm just going to back off and not stress about this,' " she said.
She continued, "I still have a good 20 to lose, but I'm not going back on camera as an actor for quite some time and I can take my time and do this healthy, and do this slow, and do it kindly to myself and not beat myself up about it."
The actress says she is also taking her placenta in the form of a pill.
"They told me that another mother down the hall had a company that freeze dries pills. This guy came, he was a total cowboy: Cowboy hat, cowboy boots … and a bag of placenta! He took it to his wife who freeze-dried it and turned it into pills and I've been taking them," she revealed