Heartbroken

My heart just broke, my daughter has finished the stash I had for her and I barely can pump at work. I've been downing lactation cookies and everything. My milk is slowly building back up but tonight after I pumped 3¼ oz I go to close the bag.... Before I know it the bag done flipped over spilling out some of the milk... I was on the verge of tears, I already feel bad because it's getting hard for me to keep up. The hakka isn't working for me at work anymore. I keep going back and forth with myself in if I should mix formula with my milk, but at the same time I feel horrible about it. I keep trying to tell myself that fed is best....