Kikelet, I'm so sorry you're having a rough time. There is nothing at all wrong with a baby your daughter's age being that size! That's a great, normal size. I think the reason some of us talk about our fat babies is not because we value fat babies more or anything, but because it's so
surprising and sort of just amazing, in the most literal sense (as in, causing amazement, not being extra good, lol). When you have a huge baby, I think you just look at them and wonder how the heck they got that way, and the whole thing seems very amusing. That's how I feel about it, at least. Plus, it's probably at the front of our minds more, causing us to mention it more, because people are always mentioning it to
us. When you have a chunky one,
everyone mentions it. All I ever hear is how fat she is, how she looks so much older than she is, how it's amazing someone my size could have a baby that big, questions about how much she weighed at birth, and on and on and on...So if I mention her fatness, it's partly because I've heard other people mention it so many times that it's on my mind, and not at all because I think it's better for a baby to be fat.

It's normal not to be rolling over yet, too. All babies get tired of being in one position after a while, so I wouldn't worry about her wanting out of the Bumbo seat. I think it's so easy to worry about every little thing when you have PPD. I had terrible PPD-OCD with DD1. I was lucky this time, but I understand how you feel. PPD is so unfair.
And that talk about fat babies and about Bumbo seats reminds me (see?

) that DD is too fat for a Bumbo seat. We don't have one, but DH sat her in one at the store the other day. He had to pry apart the leg openings to shove her legs down in there, and when he picked her up I had to pull the thing off of her. She didn't like it, either. I guess it probably isn't comfortable having your legs squished up like that.
She's not even close to getting up on all fours to try crawling, as far as I can tell, but the other day she rolled about 4 feet from where she started. I can't be certain, but it
seemed like she did it on purpose to get close to her sister, because she didn't stop until she got there, and once she did she was perfectly happy to stay there. She also manages to slide herself backwards all over the place, somehow or another. I know she isn't doing
that on purpose. She can sit up with her hands on the floor for a minute, but then she loses her balance and falls forward. She's only 4.5 months, though, so I wouldn't expect her to be sitting yet, although I know some do.
She does have stranger anxiety already, though, which I was really surprised to find out. I thought that didn't start until a few months from now, but she HATES being held by anyone she doesn't know. We just found this out when we came to visit DH's family for this weekend. She got so upset about strangers holding her Thursday night that she screamed hysterically for an hour. This was after MIL (she's only met her once) held her for about 90 seconds and we took her back as soon as she started crying. It was crazy. She did that a couple weeks ago when the neighbor held her, but I thought maybe it was her perfume or something. Apparently not.
DD also does not like changes in her environment. I knew this a while back when we had company come to town and she was out of sorts all weekend, but it seems like she is more sensitive than I thought she was. We've been here since Thursday and this baby has screamed almost the entire time. Not hysterical crying screaming, but "I'm so mad, who the h*** are all these people and why are they looking at me, and why are you trying to make me nap in this strange place?" screaming. She just learned how to do it recently, I think, which sounds strange, but we actually witnessed her trying it out a few times before she totally committed to doing it every 3 seconds, loudly, non-stop. Very overwhelming. It's kind of funny when you look at it objectively, but really, it's LOUD. At least it's not crying, so it's not so heart-wrenching, but it's still overwhelming. She's really just yelling because she's
mad. I'm sort of impressed with her ability to figure out that she can scream at us in anger, instead of crying. I know that sounds stupid, but it's fascinating to me. My older DD just cried at this age. lol