First time mom

Samantha
My two week old was doing so well, sleeping 3/4 hour stretches at night. Now all of a sudden the last 3 nights he's been up all night long and sleeping all day! What can I do if anything to help him transition back to sleeping even if it's for a little while at night. He literally did not close his eyes from 11-5 last night! Help this tired momma out please!