Oversupply to under supply...

Ka

I went from having an over supply in the early weeks (my son would spit up, sputter, push my boob away etc.). Now it seems he's eating all the time and I can't keep up. My boobs were so empty last night that I had to use formula. He had literally spent the entire day eating on me. I'm exhausted and feeling like a failure today. Anyone have tips to increase supply?