You did not fail. Your body simply told you it didn’t care what you had to do or wanted to do, it wasn’t going to let you. Exhaustion is a very strong and crappy thing that can happen, and there really isn’t much you can do to fix it except sleep, or drink a ton of caffeine all day and crash as soon as you hit the bed. I know you’ve been having trouble sleeping and that doesn’t help but you definitely did not fail you just did all that you could. Just try to focus on that sleep, maybe take it easy and spend time relaxing before trying to just jump in bed and fall asleep. There could be several reasons why you’re not sleeping so you may want to try to figure that out. I really hope your sleeping improves and that you don’t beat up yourself so much because of it.