Girls, I had loose stools for about 4 days, once in the morning, then …

Girls, I had loose stools for about 4 days, once in the morning, then took Smecta, and it stopped. And after 4-5 days, it started again ? I'm taking iron now, thinking it's a reaction from them, or is my body cleaning itself out? Although I think it's still early, 35 weeks still.