breastfed baby poop comes in all colors of the rainbow, IME. Depending on the local bacteria balance it can be yellow, green, brown, or blackish. And it can come 4x/day or once every 10 days. (my daughter did both; when she was in the 1/10 day schedule I was afraid to leave the house without a bucket after a week or so... and WOW did her farts smeel bad). So no, I wouldn't worry about the color or consistency as long as it's still not hard. Thick like peanut butter is just fine.
As for the crying, with normal newborns this evening fussiness usually starts around 6 weeks and ends around 12. I have no premie experience, but you'd be right in that same developmental period if you look at gestational age, so maybe that's what you're getting. It's simply a way your baby "reorganizes" and unwinds after a day full of stimulation. I noticed my son was particularly fussy if his day had been filled with many new and interesting things. It's just almost too much for their little brains to process without a good cry to reset them.