My cat gave birth this morning. The first cat came, she was very very freaked out about the entire thing. I could see she was in distress, then 2 hours later took her to the ER vet. They had to induce her and help her because the kitten was to large for her to get out on her own. He ended up dying after much trying 2 hours later. Now that we are back home, my cat keeps leaving her alive baby which she took under my bed and I can't get to. She is leaving it, coming to me wanting to be petted, she is walking around the house crying, I think she is looking for her other baby! What do I do? I am worried about the surviving kitten that its not going to be warm enough or have enough food. I feel so bad for my cat, I thinks he is really sad and confused.

That is typical behaviour for a cat which has lost a kitten.
One of mine did that too.

Just try to pet her and keep her near the live kitten a little while for it to feed.
Keep the mother cat well fed and cuddle her often,she will like that.
Try bundling the kitten up with some soft towels etc to keep it warm while the mother grieves.

It might take a few days for her to feel normal again, mine did,
But sadly the surviving kitten of my cat was born too weak to live for more than a week or so.

If she continues to not feed the kitten, try other feeding methods like formula milk etc, but do consult a vet as I am not very sure about the right procedure for a new born kitten being introduced to other than the mothers milk.

Yes, the mother cat is going through mourning and is searching for her missing kitten, and is coming to you showing affection wanting you to not only comfort her, but wanting you to help her find her kitten.
Was she allowed to see the dead kitten , and spend enough time with it to discover it was dead? If she had you would probably not be going through this with her right now.