Lib76, you say your DS has been on formula for 3 weeks now.
My DS1 was bf for just over for about 4 weeks and then I stopped because I couldnt cope with the stress of bf, didnt feel DS1 was getting enough, couldnt get comfortable, etc etc. Looking back,like you, i just had crap support from the health professionals.
For about 5 - 6 weeks after that, my DS1 was ff, with me trying to express milk occasionally and getting about 1oz out at a time if i was lucky.
However, on one occasion, late at night in bed, I was cuddling DS1 as he was crying and as it was, I was bare-breasted. To my surprise, DS1 just bent himself down and latched himself on and nursed. I have no idea if was latching on properly, I didnt worry about tummy to tummy, nose to nipple and all that jazz, he just did it by himself without any help/interference from me. From then on, I began bf him now and then and by the time he was 4 months old, he was being bf at least 3 times a day, obviously with ff as well.
DS1 was partially bf until he was 14 months old. I never managed to regain my milk supply in full and indeed went back to work when he was 6 months old, but the feeds I did do meant a great deal particularly after the hard time I had had.
The reason I am telling you this is that like you, I felt tremendously guilty for giving up bf, like I was a failure or unwomanly or something. But if you still wanted to bf your DS partially, then I am living proof that such a thing is possible even after a 3 week gap. Could you not just try putting your DS to the breast and see what happens or try the skin to skin thing that I have seen others on here recommending.
But I also echo what others on here have said. If your DS never sees a boob again (until he reaches adulthood that is, ha ha), then so what? Plenty of my friends have only ever ff their perfectly healthy children and ironically the child of the friend who bf exclusively for 6 months has been in and out of hospital with infections and asthma.