Please don't compare yourself to other mothers because one thing I've learned over nearly nine years of being a mum is that the ONLY people who matter are you and your baby and what works for you. Every person and every baby are different and that is why comparison is futile and generally leads to useless mother guilt.
You have done more than enough! You are obviously a nurturing, loving, amazing mum and that isn't dependent on how you feed your baby, truly it isn't.
I think for some mothers, it doesn't matter how long you breastfeed for, there will always be some level of sadness, a grieving process and that's normal and ok. It doesn't mean you have to keep sacrificing your health though - your baby's mum matters too!
I don't mean to try and influence you in your decision but I just want to say, one mum to another. You have done brilliantly.
You have done enough xx