There can be several reasons that are making your cat vomiting. Take it to vet. It is possible that your cat has eaten something poisonous and bad and that is why it is vomiting.
It can be Heat stroke so check its temperature as well. Heat stroke further causes diarrhea and fever. Give it some anti-biotic medicines for short period of time to give it relief from pain.
It can be Heat stroke so check its temperature as well. Heat stroke further causes diarrhea and fever. Give it some anti-biotic medicines for short period of time to give it relief from pain.