Tan, try not to dwell on what has happened in the past, but do your best to simply accept where you are at and move on in the present. You can't change it, but you can learn from it, and I hope from this thread that some others can also learn from your experience.
It has always been one of my greatest fears that I would be challenged over not breastfeeding, fortunately only one person ever even tried it. I guess our situations are the complete opposite in that it was quite simply impossible for me to breastfeed (no milk and the necessity of scary medications for me to be able to function on a physical level and that's before we even tough on where I was headed in terms of mental health)... and yet, I think I know what you mean. Not being challenged about your decisions isn't exactly the same as having those decisions supported.
I'm not sure if I'll ever be completely at peace with my parenting circumstances (they are not necessarily choices). I don't know if I'll ever get to the point where I'll be able to hear praise for something I don't do and not hear it as condemnation for what I am doing...
I also have to agree with the point thepixie made. If you aren't in the best headspace yourself, if you don't have supreme confidence in what you are doing (and what first time mother does?), then it is very easy to get caught up in the groundswell of opinion and get carried along to a place that doesn't necessarily suit you.
If it's this hard as a mother who FF by necessity, I can't imagine how hard it must be for someone who has chosen to FF.
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