Help what's wrong with my dog?

I came from school (half day) and my dog(Lina) was just sitting there in the back yard. She always runs up to me with her tail wagging and happy to see me but she doesn't move! My other dog chucho was running around normally and he came to me like usually. It was hot out and since lina is a indoor dog I think she didn't want to be outside I gave her water and she didn't drink, she just sat there. I said 'want a cookie?'(treat) cause she seemed sad and everytime I say that she gets so happy but this time she didn't budge I set it on the floor and she didn't eat it. I started to get worried. Then I thought she might be tired so I brought the doggy bed and put her there, she was shivering but she fell asleep. I moved the bed since it was near the air conditioning and put a blanket over her and gave her her favorite toy she slept for about 6 hours and she woke up and puked then went for a drink of water and fell asleep. Is she tired, sick? Depressed? Please help I love my dogs so much!