Am I screwed? New battery time?
Maybe not. Before springing for a battery service, consider any apps or web pages left open during that period.
Some apps and sites may continue to use energy in the background even during sleep. Remember, device sleep is very similar to your sleep. Your brain continues to function, controlling things like respiration, digestion, etc, and occasionally showing your a video—well, a dream.
You iPad is similar in that it may be polling for incoming data like mail for Messages. Some web sites seem to have developed the nasty habit of "phoning home" in spite of sleep status. I had that happen on a Mac notebook that was asleep but I'd left the Amazon home page open. When I came back to it about 45 minutes later, the charge had dropped from 85% to under 35%. Activity Monitor confirmed that Amazon was the power thief.
Try this: charge your iPad and let it sleep. This time, close all apps and webs pages before sleeping it. Leave it unused for the same amount of time and then check the charge. If it is at a high charge level, then bloated apps or sites were raiding your battery charge. If it is again near zero, see Apple about a battery service,