Welcome to HCM,
After going through your history, You got dehydrated due to gastroenteritis
which caused fluid and electrolytes loss, also contributed by effect of drinks (alcohol).
Burning in perineal area could be due to UTI or bacterial or fungal vaginal infection
Your pan in stomach may be due to colic of intestinal origin or alcohol induced gastritis.
You should see a Gynecologist and get yourself examined and investigated with CBC( Complete blood Count
) and urine R&M and culture with liver function tests and Abdominal sonography
In the mean time keep yourself hydrated with fluids and water and if any fever a paracetamol
If by any chance possibility of pregnancy is there test for it and it will be managed accordingly.