Yes indeed Chamomile is a relative of the Ragweed as well as some foods such as sunflower seeds, Cucumber, melons and Zucchini are all relatives and in the family of Ragweed so if you're allergic to Ragweed you'll be allergic to those foods which can cause swelling of your mouth and throat if you're allergic to Ragweed.
So if you're allergic to Ragweed you'll be allergic most likely to Chamomile and should avoid Chamomile Tea or anything else with Chamomile.