Breastfeeding/stomach troubles

I don't have anybody I can vent to who understands what/how I feel...I'm just so upset because I'm a FTM and my son and I were able to pick up breastfeeding from the get-go without any issues. He hasn't had any problems latching, I have never had any pain, I've had a good supply. I've wasted money on a breast pump, nursing bras, nursing pads, and spare parts to be told at 6 weeks that I have to switch to a special formula because my son has a dairy allergy. I'm so heartbroken because I've just wanted to be able to breastfeed my son, I know it's not breast is best, but fed is best yet it's so hard to accept.