What kind of tea was it? I was thinking about having a cup of chamomile tea last night (sans Kava) and found something interesting upon doing some research, although it might be obvious to most people here on the forums:
The general consensus within the field of herbal interactions is that you will experience a heightened sedative effect when combining any other herbal sedative with Kava.
Was it just regular black tea? Maybe the caffeine has something to do with it? I've read that tea contains significantly more caffeine than coffee.
Stimulants: (coffee, kola nut, máte, guaraná)
Unfortunately, there isn’t too much information available with regard to the safety of combining Kava with herbal stimulants or their interactions. But, generally speaking, it’s unwise to combine kava kava with any herbal stimulant, and probably any synthetic stimulant as well. Quite generally – it’s unwise and counterproductive to combine stimulants and sedatives, because of their counteractions on the same or relatively similar biochemical compounds [6]. If you’re looking for something to calm you down, you take a sedative — you don’t want to then take a stimulant and undo what you’re trying to accomplish.
For example, coffee and Kava probably interfere with each other and their relative performance. It’s quite possible that Kava aggravates dopamine or dopamine receptors, meaning that it interferes with its release [2]. If this is the case, then something like coffee – a natural substance that stimulates the release of dopamine [7] – will naturally compete with Kava because each is trying to do a different thing to your biochemical system.