I agree with Been There. Sounds like you might need to adjust your schedule. Do you work 12s? Was the last shift a 12 hour scheduled shift? I'm assuming it's not or it would put you into OT, depending on the days that you worked.
It's really hard to get through the week sometimes; we've all felt extreme exhaustion. Calling out an hour prior to your shift means that your colleagues will have to work harder, because there is little time to call in per diem staff. But you know that.
This is a learning experience for you. Talk to your NM about adjusting your schedule so that you can break up the week. Believe me when I tell you that it's worth it!
For the last 3 years, I worked 4 10s in a row, and had every Friday off. Seems like a sweet schedule, eh?
I was so exhausted at the end of the day on Thursday that I did nothing but sleep/lounge around on Fridays. I was a total bump on a log. I worried the whole day because I had stuff to do, but simply COULD NOT muster the energy to get anything done. I felt like a complete loser.
When I changed my schedule so that I had Thursdays off, I can't even express to you how delicious it felt to leave my alarm clock in the "off" position Wed night. I was actually productive and got a lot of stuff done on Thursdays, and went to bed early so that I could feel refreshed on Fridays.
Now, I wake up every Friday with a smile on my face, knowing that I just have to work one more shift till the weekend!
A break during the week is refreshing, and will give you more energy. Keep us posted.