It's probably the German Chamomile (Matricaria recutita), and believe it or not, it's the one most commonly sold OTC - simply because it 'grows like a weed' and is therefore a good business option. And, also believe it or not, it has the same medicinal actions, and is used in the same way, as the more well-behaved Roman Chamomile (Chamaemelum nobile).

The ball's in your court as to whether or not you keep it!