Rozanskyism,
These are all wonderful answers to your questions. But as stated, each person will have a different experience. I apologize for the long post in advance.
How often will I need to empty and change the bag? -
Depending on if you're using a 1 or 2 piece system and depending on your diet as stated, will determine how often you have to empty/change the pouch. I have an ileostomy due to Crohn's disease and I'm assuming that since your colon is being removed, that's the type of ostomy you'll have. I use a 1 piece drainable pouch and I change it every 3-4 days. I empty the pouch anywhere from 5-8 times a day. A lot of members here prefer a 2 piece system where the wafer and pouch are separate and snap together. From what I've read, the wafer can last as long as a week before needing a change and you can alternate between drainable and closed pouches.
You will acquire your own method that works best for you on changing your pouches. There are several videos on YouTube on how to drain/change them and you can always ask here what works best for other members.
Is it painful? -
After my surgery, I was just sore. I had a morphine pump but the doc said the sooner I was off of it, the sooner I could go home. And with that type of surgery, a lot of air gets trapped in your body cavity. It takes time to dissipate through your skin and can be uncomfortable. It's kind of like a dull ache. The stitches for me start at mid chest and end just above my groin. I felt hunched over because I didn't want to rip the stitches and it will take time to get back to a normal posture.
What should I expect my first month to be like? -
Immediately after surgery, you will probably have a tube down your nose into your stomach and ice chips will probably be your diet for the first week. The second week, they will take the tube out and you will probably be allowed clear liquids or surgical soft food. When the doctor allows you to have solid food, chew your food up very, very well to avoid getting an obstruction or blockage. I learned the hard way by eating peanuts without chewing them up well. I had an obstruction and it was like rolling gas pains. You'll want to avoid any naturally fibrous foods like raw fruit/veggies for a while until your body heals and adjusts. I had surgery 23 years ago in the month of October and I was able to eat everything around Thanksgiving with no issue.
Allow your body to heal. Don't do any heavy lifting for a while. You'll be able to strengthen your stomach muscles slowly and carefully to avoid getting a hernia. You'll learn what foods agree/disagree with you and after a while, you'll see your output will slow down depending on what you're eating/drinking. Average meals go through me after about 5 hours now. Orange juice or beer goes through me after about 2 hours. But I love both so there's no way around that....lol
You might go through some depression and have a warped body image. I was in a slight funk for the first couple of weeks but I realized that I was no longer running to the bathroom with any sense of urgency where as before the surgery, it was every hour on the hour. I no longer have to take medication for my Crohn's and I am completely pain free. I was able to go back to work 2 months after surgery and that job required me to be on my feet 8-12 hours a day.
Please let us know if you have any other questions. Hope this helps.
Bain