I've quit. Got back on and quitting again.
Your tolerance just goes up and up and up. First time I quit I was using 200mg of oxy a day.
What you're experiencing is withdrawals. Google opiate withdrawals and withdrawal remedies. You're going to feel like crap (well, not feel 100%) for a week or so.
The pills are making you crave them - not you. Withdrawal sucks. You count the minutes. It's a rough ride but you get over it I promise. It is absolutely doable. If you need help - please ask for it. I wish I did. I really did. You forget that you can be happy off of them. I forgot how great I felt without opiates. Much better than anytime I was on them.