5 week old sleep

My LO slept for 5hrs straight two nights ago (yay!) But that was the first time and the only time. He's up every 2hrs every other night and is constantly squirming, grunting, squealing. He's EBF. I'm so exhausted. I know reflux to an extent is normal in infants but is this the cause of his nighttime activeness? Or is this just normal behavior? How are you all dealing with the exhaustion?