Breastfeeding supply dropped

I was feeling very drained from pumping (I exclusively pump). My baby is 4 weeks old. I have a serious love/hate with EP, and somedays I have no desire. Over the last few days, I was going 5 hours between pumping, and one night my baby slept almost 7 hours and I didn’t pump. Man, was that a painful and messy wake up. I have noticed my supply is lower over the last day, and I know I did it to myself. Is it possible to get your supply back up? If so, how long does it take?