What Causes Swelling In Breasts With Tenderness?

I woke up this morning and both of my breasts were extremely swollen and very tender and hard. Quite a few of my montgomery glands were also swollen with little white heads. Any idea what could have caused this? I should mention that I normally eat all natural, but last night I went out with my husband and consumed processed/high sugar foods at a dinner theater. Could that be related?