H.G.
It's so easy to get depressed after a baby is born- and it can happen anywhere up to a year or more after the birth! When you're on your own a lot, it's the worst. Please find a counselor to talk to. I did, and it made a huge difference!
In terms of food, maybe skip the cereal? Try applesauce! Dip your finger in it, and offer it to your daughter. Then try a small spoonful. You can also do pears or sweet potatoes, which most kids love. Or mix one of those into the cereal. Breast milk is a mild flavor, when mixed into cereal. I doubt she even notices that it's the same thing she loves so much from mommy! :) My son never liked cereal unless there was fruit or veggies (or both) mixed in.
You can also put a piece of soft cantelope into a mesh feeder, and let her chew on it. Lots of little ones love that! Banana works too.
Keep trying! She'll get the hang of it!