Diarrhea for 3 days now 31 weeks pregnant?

I've had diarrhea for 3 days now. I have no other symptoms. I'm 31 weeks pregnant and on modified bed rest for preterm labor. I have had contractions on and off but nothing too serious. I do not feel sick to my stomach and I am not running a fever. I am not lactose intolerant and do not change my cats litter box. I am 25% effaced but not dilated. The baby has been moving perfectly fine. I went to my ob office yesterday and I am in perfect health according to the midwife. I have increase mucous like discharge but my water has not broken. The baby is engaged. Am I getting ready to go into labor? Also, I was bottling my leaking colostrum since I think it'd be stupid to let it go to waste and giving to my toddler who is 21 months old (I have been just sitting with a bottle underneath my nipples to catch it I have not expressed it) but now it turned from yellow to clearish white so my actually breast milk is coming in. Is this labor? I was induced with my first so I don't know what the signs of labor are. OB office doesn't seem too concerned.