Your reaction surprises me, to some extent, for you feel no warmth nor any euphoria, at all. But, I will say opiates are definitely an acquired taste, and bring forth a very powerful and lovely, but subtler type of high, on the whole. You are experiencing some typical opiate effects, however. You are feeling nausea, irritability (this is common, even right alongside euphoria), and you are having some phenomena with your hearing (this last effect I have heard of, particularly regarding hydrocodone, and while not common, not uncommon - I experience it sometimes with opiates). With opiates, this type of reaction isn't too uncommon for someone who has never taken an opiate before; in fact, some people do dislike opiates, on the whole, reporting subjectively undesirable feelings which are more prominent than any desirable feelings. Still, I am surprised - I would have thought a solid 20 mg hydrocodone for an opiate-naïve individual would have gotten you anywhere from pretty high to high as a kite. I, personally, recommend 15 mg hydrocodone for most opiate-naïve individuals looking for a nice opiate experience, neither too underwhelming nor too overwhelming. And, I usually tell them just to take that without any other drugs like anti-histamines such as Benadryl, unless they take other drugs regularly and are dependent on them. Benadryl is used by many opiate users, and by the many reports I have heard, can increase the enjoyment of the opiate experience, yet I think it is best that one feels an opiate as it is before throwing anything else into the mix. Still, I don't think the Benadryl soured it for you - your dose of Benadryl was fine; frankly, I think you are just one of those who does not enjoy the first experience he has with an opiate. Just be very, very careful with them; they are insidiously addictive drugs.