Probably about a week for the acute withdrawals, and then another week of feeling a bit shaky. How long have you been taking them? Many people experience something called PAWS (post acute withdrawal syndrome) after the acute withdrawal is over, which consists of low energy, depression and anxiety, and that can linger on for months, although the less time you've been on opiates, the shorter than will last (and sometimes it's not experienced at all... honestly I've never really had PAWS very much and I've been on and off opiates for 10 years).
Do you have the restless legs? You didn't mention it so I'm thinking maybe not... for me it's one of the worst parts. If you don't have it then you probably have a mild withdrawal and likely you will recover pretty quickly.
The hardest part will likely be ignoring the cravings in the future. Once you've been addicted to opiates, cravings may happen periodically for a long, long time, or maybe even forever. I have quit many times, once for a full year, and I always eventually relapsed. All it takes is one moment of weakness, at any point, and the cycle continues. If you get clean and then even a year later take another oxy, you will pick up right where you left off. It won't take days on end of taking them to become re-addicted, like it did the first time. We are very good at rationalizing to ourselves, so if you ever find that you are saying to yourself "hey, I've been clean for a while, I can responsibly use opiates now, I'll just do it this once", REMEMBER that you're lying to yourself. If I could have remembered that, my life would be very different right now.