Why am I experiencing a painful period which includes vomiting, nausea, diarrhea, pain radiating to thighs and all over, and fainting?

Prostaglandins. If this is the first time that has ever happened call your ob-gn. If it is not then pro inflammatory prostaglandins are contributing and things like vitex and omega three fatty acids can help over time. A miscarriage could be a possibility so call your doctor.
Endometriosis? It is possible that you have endometriosis. It is also possible that at least some of your symptoms are related to prostaglandin release that accompanies your period. If this is a recurrent issue for you, see your doctor.