Since having my son I have noticed I wake up routinely throughout the night, is this normal?

So I have noticed that despite him sleeping through until he needs feeding and changing. I will often wake up before him and end up staying up long after he's gone back to sleep.
Today is an example of this. He's at my mum's and I've woken up at 2am and it's currently 4.25am . The rest of the day I'll be shattered.