good advice all around. Basically you're playing with fire when you take oxy. The rare person can balance it out and keep it just for weekends or the odd occasion, but most other people get hooked and it starts to take over their life.
You can get away without feeling too shitty by just taking it for 1-2 days. once you start taking ox for 3 or more days and stop, you'll go though withdrawls. Extreme exhaustion is one of them that's not fun. You'll just want to lie in bed all day and night. I think the reason is because you don't get in your rem sleep on ox. You sleep very lightly and wake up a ton throughout the night. Once your off Ox, you may notice things that never hurt you before begin to nag you. You're lower back may become sore, athritis may all of a sudden flare up or your joints may feel brittle and nag with pain. This will last a couple days before feeling normal again.
It's also tough for those that get hooked to have to experience life on a normal scale once again. If you take an ox, you'll have the most perfect day and you will feel totally in control and strong. It's not like coke or E that makes you feel kinda loopey and fuked up. It's a super clean high and you'll find yourself enjoying just about everything you do. That's the problem though, once you go off you'll remember how much fun you had doing the most boring things and that itch to take them will come back.
Like I said, it's playing with fire.