One month old poop

My baby’s poop is vary water she hasn’t been eating much last night she went 4hr stretch with out wanting to eat and she fell asleep and this morning she went on a 5hour stretch with out eating. He keeping fighting with my breast and no latching or only latching for a few minutes. Has been a bit fussy hasn’t been taking her naps. B4 she poops she cries a bit. And then stops when it goes throw her. I was changing her and her poop was super watery. Can any one related of have experienced this can give any advice. Should I take her to the doctor. Her temperature is normal