Yeah, benadryl is good stuff. Non-addictive, and can knock you out. I just don't use it because it leaves me drowsy in the morning, and believe it or not has caused sleeplessness with me before. Frankly, I rarely take anything because I can't stand taking pills.
But, yeah, ANY herbal remedy needs to be checked with your doctor. Just because they are "natural" and largely unregulated does not mean they do not have medicinal properties, and along with it, potential side effects. There are chemicals in herbal remedies just like medicine. Some herbal remedies are quite powerful. I just suggest chamomile because it is mild, with no side effects that I'm aware of, and frankly, it works for most people.
Hope you get past this and get some deserved rest!