18 month sleep regression...?

Tessa

I honestly don't know if this is considered a sleep progression at all but all of a sudden over the last few weeks my son has decided to start waking up super early in the morning somewhere between 4 and 530. He still sleeps through the night without waking but he used to sleep in until at least 6:30 but now he's up super early every day and will not go back to sleep!

What can I do? Is this just a phase that will pass? Or how do I handle this 😅