Thawed milk

I broke into my frozen stash tonight, and thawed some milk out by running hot water over the bag. After I put it into the bottle and started feeding her, I noticed it was chunky. It smelled normal, and it was only pumped and frozen last week, so I know it wasn't bad, but I'm wondering if this is normal? Could it have something to do with the quick defrost? Or is this just how milk thaws?