Ok, in know it's not the same, but I had a breast reduction earlier this year. I was a 28j and the **** things were giving me so much back, neck and shoulder pain. I was a 28 back so it was very unlikely that losing any weight would have made a difference.
Anyway, I was struggling with back, neck and shoulder pain. This was leading to bad headaches and problems with my spine. They were also causing a range of emotional and psychological issues.
I decided that a breast reduction operation was my only option (after exhausting and and other available option). Some of my family were really opposed to me having this op, similar to your friends are now.
I really felt like this was my only option and there really weren't any other options that I could see. I went ahead with the op and it really was the best decision I have ever made. I'm a 30b/c now (still a bit swollen), have no back ache and am in proportion for the first time since I was a teenager!
As I said, completely different op but I still had to face the potantional complications and a load of resistance from friends and family. The important thing is that you do the op for you. You need to be aware of te potential risks and benefits.
A gastric bypass will mean that you have to eat smaller meals for the rest of your life, but you seem to be aware of this and, more importantly, happy with this. Sure, there are a lot of other considerations but, again, you seem to have taken these on board.
All I would say is make sure you have weighed (no pin intended!) up all the options as make this decision for you. Once you have decided 100% what you want be clear with your friends and family - this is you decision and you have made your mind up. While you appreciate their concern, you need and want their support, nor their criticism.
Hopefully somebody will be a long soon who has actually been through the gastric bypass op. Unfortunately there does seem to be a lot of stigma around this type of op, so you probably will get a lot of opinions thrown your way. Consider all the pros and cons and make the decision that is right for you - only you can make that (with input from your doctor).
I am going to stop waffling now and go tend to my hangover (I only had two glasses (albeit large) of wine. Such a lightweight. Pathetic!). Good luck with everything. Take care.
Emma x