The next hour is not for deciding what it was. It is for keeping the three things that let somebody else decide, and the first of them goes down the drain.
Constipation is the first side effect on the list for iron tablets, and iron supplements also sit inside the advice for preventing it. Three of those four fixes are yours. The fourth one is a conversation.
Itching with nothing to show for it is the version that gets a phone call today. Where it itches, when it is worse, and what you are actually asking them to test.