Minecraft Won't Log Me In?!

So, With 1.6.2 and 1.6.1 here, I tried to update my Minecraft, everything went smoothly at first, I downloaded it, installed resource packs, ect. Though, a few days later I tried to log in and with the new launcher, the play button in the bottom right corner didn't light up or whatever it does. It stayed grey. So then I exited out of Minecraft, started it up again, log out and re-log but it stays the same. I tried downloading it again many times, but it still won't let me log in. Is there anyway I could fix this? Please tell me if you do know how I can. I do have a MacBook so anything from Windows won't really work. Again, Please help.