TMI but advice please

so I’ve had diarrhea the last 3/4 days and low abdominal cramping every time I lay down on my stomach I try to fall asleep on my side but wake up on my stomach and I’m cramping so very bad. Then it’s like diarrhea again. Idk what is wrong with me I’m 18 weeks & 3 days I definitely wasn’t like this with my son. Anyone ever had this problem the cramping is terrible.