Sorry friend water or gatorade are not going to spare you from a fatal overdose.
You are dancing with the devil here. I recently overdosed on fentanyl/xanax/ketamine/alcohol (all low/moderate doses...).
It really depends on your tolerance but DO NOT TAKE THIS AS ADVICE TO CONTINUE!!!!
If you are combining benzos with opioids you need to keep one of them at a minimum. Like 2mg xanax + opioids or 20mg oxy + 6mg xanax... you are pushing limits unless you have a massive tolerance to both.
If you're not feeling good on what you've already taken please just stop. Not worth it. Don't die. Be safe my guy. This is a potentially FATAL combination.