night shift supervisor with no oncall back up

So, here is my situation..I am a night shift supervisor for a 186 bed facility. Noc staffing is 2 nurses downstairs for 80 residents, and 2 nurses upstairs for 106 residents. There is no difference in acuity on both floors as PEGs and wounds and all the other fun stuff is pretty much randomly distributed throughout the house. (ideally), We get 4 CNAs on the 1st floor and 6 on the 2nd floor. Most nocs its more like 3 down and 4-5 upstairs. The get up list has 45 people upstairs and 20 downstairs and doesnt change regardless of how many CNAs we have that night.

Anyways,,

When a nurse calls in, I have to take their cart for the shift, plus do all my supervisor duties. There is no 'on call' that I can get to come in. I try to get the 3-11 folks to stay over or at least pass midnight meds, then I try to get AM folks to come in early, I call PRNs etc....bottom line, if none of these actions work, I am stuck on the cart.

Recently, I have had to take both carts on the 2nd floor (106 residents) by myself because staffing screwed up and scheduled people that were supposed to be off, or people called in. I have done this 5 times in the last 3 weeks! Plus when the 'man' comes in in the morning, they expect that I have completed my supervisor duties regardless of how many residents I had.

The second night this happened, I attempted to call the unit manager in to come and help...Well, she did not pick up the phone but I got a chewing out in the morning..."Dont ever call me at noc again unless its emergency, Its your job to find coverage for your shift and if you cant well, you just have to work it" I mean 4REAL!!!

This has turned into a vent session...

My question is, how do others handle such issues? I know I probably need to get busy looking for another job coz this is ridiculous, but how do others handle call ins?