Hard to answer your question without knowing your rough location and cold hardiness zone. The good news is the seeds are cheap and it readily sprouts.

Just for fun I'll mention that the Chamomile tea available in stores is typically "German Chamomile" which is NOT a close relative of true chamomile!

German chamomile (Matricaria chamomilla) is an annual plant and it lives for only one growing season. Roman chamomile (Chamaemelum nobile) is a perennial and is the other most common chamomile species. If it is truly german chamomile I wouldn't expect it to re-sprout in the spring though it may have self sown seeds which can sprout.

FataMorgana

Roman Chamomile is not used commercially to make Chamomile Tea (in fact banned in some localities) due to dermal irritation -- esp. in the throat.

Here is a link that might be useful: Safe and Poisonous Garden Plants

I suppose I will have to re seed them in spring since even more seem to be sprouting.. I may be able to set the planter in my greenhouse but it still gets a bit cold inside just doesn't frost

I wouldn't be at all surprised if your self sown German chamomile survives the winter for you as seedlings. It certainly does here.

Regarding your garlic sprouting, it is very hardy and is just doing what comes naturally. Don't worry about it.