some of your symptoms are suggesting pregnancy
Better you go for urine pregnancy test to detect the possibility of pregnancy.
The other possibility is you may be having gastritis
, as you are having heart burn and nausea
this possibility is also there.
one more possibility is irritable bowel syndrome
but vomitings are not common in it.
You didn't mentioned the date of your last menstrual period, if your periods are delayed for more than 1 to 2 weeks, consult gynecologist get examined and take transvaginal scan which will rule out your doubt.
Try to use some proper contraceptive
methods with advice of your gynecologist to avoid such things in future.