Breastfeeding has to end

So my journey has to come to an end. I am completely distraught over this. I wanted to continue breastfeeding until a year. That was my goal with this one. But I went back to work and knew I would be formula feeding. He does NOT do well with both formula and my breastmilk. My breastmilk has always made him more gassy and spit up more. I don’t know WHY this bothers me so much that I have to stop. No one will understand that boding feeling you get when you breastfeed. My heart is sad, but my son is happy. And at the end, that’s all that matters. I went 11 weeks. I just wish I didn’t feel like a failure.