I heavly drank yest for the first time and smoked weed, now i'm vomiting blood and having severe stomach pain, what should i do please?

Go to ER: You need immediate evaluation , possible ulcer bleeding or even a tare in gastroesophageal junction.

Alcohol: Go the nearest emergency room for immediate treatment, these are serious symptoms. My best.

Vomiting blood : Apparently the heavy alcohol drinking caused a stomach uler or erosion in the esophagus, people with alcoholic liver cirrhosis can develop esophageal varicose veins that can bleed. You must go to the ER ASAP to stop bleeding & a gastroentrologist do endoscopy to find the reason , lactation of the bleeding. Good luck.