Why come down? I usually keep going until body cant take no more and i have to sleep (within 2-3 days) I used to have benzo's etc to come down but tbh they caused even more problems in the end.
If you have to, then some Diazepam, alprozolam or nitrazepam but try get legit ones because the pressed benzo's are dangerous (I speak from bitter experience)
If it's feasible to stay awake, thats what i'd do, keep going, but EAT IF YOU CAN (bananas, melon etc) , plenty of water. By tonight you should be ready for sleep, maybe a couple of cheeky whiskeys just before bed.
Alprazolam(Xanax) is the best because it hits quickly and it has lower half life than other benzos. Lorazepam works too and has approx the same half life.
Please don't use diazepam(valium) or clonazepam(klonopin) for sleep. It takes a very long time to get these out of your system.