It's definitely something in the nightshade family. Many of these are common weedy species and can appear just like any other type of weed. Feel free to remove :-)

Okay. Thanks. I read they can be poisonous....I ate half a leaf but I think I'll survive :)

It depends on the nightshade :-) It's a big family and some are commonly grown as vegetables (tomatoes, peppers, potatoes, eggplants) but even those can have some toxic components. It is best never to eat or taste anything growing unless you have a confirmed ID.

One of the various manifestations of Solanum nigrum, Black Nightshade, a common, and toxic, weed of cultivation. I would reiterate, please do NOT eat stuff you cannot identify. Your herbs would all have distinctive strong scents. No need to taste them until you are certain.