I also struggle with insomnia. Most people who take melatonin don’t understand how it works. They pop it right before bed and expect it to make them tired. It doesn’t induce sleepiness per se. That’s probably more of a placebo effect if people are popping it at bedtime. I’d talk to a doc about a prescription option if you regularly struggle with sleep. Something like Trazadone is pretty safe and not addictive.
For tonight, just accept that tomorrow will be tough. You’ll survive it though.