Help! My 3 week old DD has had two dark green really runny, diarrhea diapers in the last 24 hours. I…

Help!

My 3 week old DD has had two dark green really runny, diarrhea diapers in the last 24 hours. I called the pediatrician's office after the second one and the nurse said it was fine. Last night she screamed on and off (mostly on) for THREE hours, I tried nursing her, she refused, I gave her gas drops, bicycled her legs, changed her diaper, I just couldn't get her to calm down, after she finally went to sleep she was great and slept most of the night. This morning we wake up and all is well, I can tell she's trying to poop/poot because she's grunting and straining a little, she got a little fussy but nothing too bad. Well when she had the second diarrhea diaper and the nurse said it was fine about ten minutes after she starts crying again, I do all the things mentioned above and I couldn't get her to calm down for about 45 minutes. Is this normal newborn behavior?! I don't remember my first DD doing this, I mean I remember the frantic newborn cry but the boob ALWAYS calmed her down or a diaper change lol.