darkened ring around nipples - repost?!

I haven't changed my pill, but I started my new pack on the 16th feb after finishing it three weeks ago.

I had my weeks period break after finishing my last pack, but I hadn't time the week after to go to the docs and get a new pack (due to work etc).. so in that second week of not being on it, my boyfriend and I just used condoms -

(probably a bit tmi, but after we'd finished my boyfriend somehow ended up with semen on his fingers, so I checked the condom thorgoughly and even squeezed it, but I found no hole.. so it don't know where that came from!)

to sum up, basically its been 2 weeks since me and my boyfriend last had sex and a week since I've started back on the pill, I only noticed today a darkened ring around my nipples...
Now this may have been ther before and I've just never noticed it, unless they have darkened which did cause me to notice it earlier!..
Could being back on my pill have caused this?, they've also been SLIGHTLY tender for the past 5days now (i'm only in my first week still)x