Constant straining

Wendy

My baby girl is 7 weeks (born 4 weeks early) and is constantly straining. I mean ALL day long. I have asked multiple pediatricians and they all say it’s normal, but I’ve never heard any other baby strain as much as my little girl does. Sometimes it’s to the point where she’ll throw up. She also does not do well sleeping through her naps, the straining will wake her. Anybody else??