I've never had them until now
There are a lot of reasons for dark circles. -Allergies -Dehydration - Lack of sleep - Iron deficiency etc. If it is severe and you are feeling tired with it I would suggest that you see your doctor for some blood tests. http://funadvice.com/r/14qc4uef977
Whenever you have dark circles under your eyes, it usually means that you are not getting enough sleep at night. If that is the case, all you need to do is for sure get more sleep and put on some concealer.
You have not been eating well, or you could not be sleeping good, or you could be sick and stuff of that kind,
I have the same thing and it could be because your immune system is weak and more sleep might help.
you could be under alot of stress, you might need more sleep, or a combination of both
more sleep probably could help