I was devastated when by first baby was wasting away on breast milk. Eventually at 12 weeks we found a formula that he could digest and I was comfortable weaning myself off the pump. My second child was prem as well but I had more support and success. At 20 months he is still a boobies boy but at least no longer through the night.
I've just found another 60 mls of breast milk in the freezer. It's been there a year, might throw it into a loaf of bread one day.