It was just after surgery for diverticular disease, and Greg Saggio, 48, was feeling good. That night he was already walking around. By the next morning, he started to eat.

But then he went home and — ignoring his doctor’s advice — went right back to work. Just 1 week after surgery, he was commuting 50 minutes twice a day, wearing business suits that restricted his movement, and eating large meals.

His attempt to quickly get his groove back was a big mistake. Saggio was socked with pain, discomfort, and diarrhea — and had to press the restart button on his recovery.

As a general surgeon and assistant professor at NYIT College of Osteopathic Medicine, Saggio knows he made a classic post-surgery mistake. He pushed too fast after he left the hospital.

“You think you can do everything,” he says. “You think you’re better than you are, you eat too much too quickly, you go up steps too fast, you go out and drive, and you get bounced around.”

Keep your own recovery on track and avoid these costly mistakes.

It’s an issue if you get active too quickly, says Jonathan Whiteson, MD, director of cardiac and pulmonary rehabilitation at Rusk Rehabilitation Center at NYU Langone Medical Center. If you jump the gun, you may fall and get hurt. Your wound may not heal properly. Like Saggio, you may end up at square one.

Your doctor gave you specific dos and don’ts. Pay attention to them. Maybe you have a green light for simple activities, for instance, but a red light for strenuous ones. Or maybe you’re supposed to walk every day but not lift anything over 10 pounds.

“Stick to what your doctor tells you,” Saggio says. “Don’t overdo it because you will have setbacks, especially with heavy lifting.”

As soon as you’re cleared to move around, do it. People are often worried or scared about it, “but one of the most important things after an operation is to get mobile,” Whiteson says.

Lying in bed can trigger a host of problems — blood clots, pressure ulcers, pulmonary embolisms, and weakening of your muscles.

Even if you feel tired, resist the urge to sleep it off. When you move around it actually shakes off fatigue. It also speeds digestion. Your bowels may be sluggish after surgery, but a little physical activity helps wake up your gut again, Whiteson says.

You may shrug off pain medication because you heard it’s addictive or it makes you constipated, nauseous, or woozy. But skimping on your medicine isn’t smart.

Pain can sometimes interfere with your sleep, appetite, and ability to get around, Whiteson says. And that can make it harder for your body to heal. Ultimately, the goal is to get off medication, but not before you’re ready.

If you feel queasy or haven’t moved your bowels, it’s only natural that you may not be in the mood to eat or drink. But it’s important to “refuel.”

Food gives your muscles energy and fluids keep you hydrated. When you don’t get enough, your recovery can stall.

A lot of people think they can tough it out on their own, Whiteson says, but it’s important to work with a physical therapist.

One or two sessions before you leave the hospital may be good enough after some types of surgery. But if you had a major operation, physical therapy is key. It can help you get stronger and recover safely. Take it seriously. Keep your appointments and do your at-home exercises.

Like Saggio, you may be tempted to return to your job ASAP. But don’t give in.

“I’ve seen plenty of people try to do work while they’re still in the hospital — with a computer and cell phone,” Whiteson says. “They’re not coherent, let alone able to make good decisions.”

Plan in advance for time off and ask your doctor when you can return.

If your doctor tells you not to get behind the wheel — whether it’s for 2 weeks or 2 months — it’s for a good reason. Your reaction time may be slower and you could get into an accident. Until you’re ready to handle it, get lifts from a friend or family member. Or ask them to do your errands for you.

If you’ve had surgery on your belly, heart, lung, or spine, your doctor may give you exercises to help your lungs recover from anesthesia, the medicine that kept you pain-free during the operation.

“Doing breathing exercises is very, very important,” Whiteson says. It expands your lungs and removes mucus that gathers there. Don’t quit until your doctor says you can stop.

To keep your recovery humming along, follow your doctor’s directions. As Saggio knows well, taking things into your own hands can slow down the healing.

“I was a little stoic. I definitely rushed my recovery,” he says. Next time, perhaps, he’ll take that extra week off.