Well......
The chamomile could have, if it had been consumed, considering the medication in question and the actions of chamomile.

Chamomile and lavendar both work on the nervous system with Lavendar being the stronger. But in the tea that you listed you also had "may pop" (Passionflower) which works on the nervous system as well, as does the lemon balm. Chamomile is by far the more benign of this little group ( nervines) but there is no telling how they will work with a medication like Sensaval (Nortriptyline). The research just hasn't been done. While peppermint has some relaxing qualities it is not considered a nervine but a digestive so I don't think that it would have caused any type of reactions.

Thinking about this a little more in the time I had yesterday ( considerable amounts of time, I drive 5 hours a day for my job) It could have been the combination of herbs as well. you may want to avoid combining this class of herbs all together. Stick with "simples", one herb at a time, and avoid herbs like Kava Kava, and Valerian. Two of the most powerful of the nervine class. As a matter of fact Kava not only works on mood but on pain as well by taking up space on the opiate receptors without the euphoric effects of opiates. It's quite hard on the liver with long term use though. Kava and Strong infusions of mint ( mixtures work better than simples for this) help to relive joint pain from arthritis or just plain old overuse.

Ok I'm moving on now.