Breastfeeding supply help - question

So I was away from my baby for a period of 24hrs. During that time I pumped every couple of hours as my boobs hurt if I go longer than 4hrs without expressing.

Anyway today I am back to breastfeeding my baby and the mornings seemed fine but by this afternoon my breasts felt very deflated/empty.

When I tried to feed my baby at 7/8pm he kept screaming and was on and off the boob.

I think my milk has depleted?! Is this even possible in a 24hr period?!

We had to give baby formula and right after that I tried pumping and got half an ounce. Now I’m stressed and don’t know what to do.

How is it possible to go from a great supply to what seems like no supply in a day?!

What can I do to get my supply back to normal. I’m 5 weeks PP.