To the OP, some of these responses had me :banghead: because I think a lot of people just saw the thread title and responded to dealing with low energy and not that you are so close to stepping on stage.
Obviously what you're dealing with comes with grinding out the last few lbs right before a show and need a little boost to get through, not a long term solution to low energy/lack of sleep.
Like Stewie said BHB is something to look into. Being so close to a show and on low carb, I think it'll be the most noticable since it isn't a stimulant. I started incorporating it pre-workout last time I prepped and definitely helped.
Just note that BHB does have calories. Not worth worrying about in most scenarios but if you're so close to a show and counting everything, just make sure you track it.