Accidentally drank a cup of chrysanthemum tea 6W4D

I understand the worry, but one cup shouldn't cause any harm at this stage. A lot of mums worry about chrysanthemum tea in pregnancy because traditionally it's thought to have cooling properties, but a single accidental cup is really not a big deal. If you're feeling anxious about it though, might be good to give your PD a quick call just to put your mind at ease, they can reassure you properly.