10 week old not wanting to eat!?!?!

My 10 week old woke up this morning and doesn't seem to want to eat.... it had been 4 hours since she had eaten (she woke up at 430 this morning and drank 4oz) I tried again at the five hour mark and still cried every time I tried to put her bottle in her mouth. She was happy and cooing this morning. She had her two month shots on Wednesday. I emailed her dr. Already, but I wanted to see if any other mommies have had the same issue. She drinks formula btw. Thanks! Ftm and I'm freaking out!!!