Does my baby have diarrhea??? Please help!?

I have a 8 week old baby, we have had so many issues with formulas becuase I could not feed. Please dont lecture me on not feeding, i just couldnt do it. Anyways, so we tried about 8 diff formulas. Each one would make her constipated, inc: reg enfimil,gentlease, low iron,prosobee, nestle good start reg and soy, Isomil was the first not to make her constipated but made her vomit, no we are on Nutramigen, she has been doing really well with this, her stools are really soft, i can not tell if they are runny or not, they are yellowish green, grainy, really soft almost runny, kinda stringy, they have been this way since we switched a few weeks ago, i dont konw if its bad, she poops about twice a day, and sometimes will end up with a little in her diaper here and there. it sounds runny when she is doing it but I dont know. is it diarrhea? Should i be concered. My hubby is taking her to the WIC doc today but i want to ask others opinion to see if I should take her to the real doc?