Welcome to healthcare magic,
Acute diarrhea without fever in pregnancy
,the main concern for you should be to avoid dehydration
.As far as radotril/lomotil are concerned they are a no-no because pregnancy itself with its effect by progesterone
already have reduced motility and with radotril/lomotil it can further reduce this motility leading to constipation
and in extreme cases paralytic ileus
.Anyways as one of my colleague suggested you can take probiotics like sporolac for the diarrhea and just take ORS to avoid dehydration.Apart this keep a healthy life style of eating/exercise and sleeping.Take good rest.
Hope your queries have been answered well.
Have a healthy life.