Thanks for your question.
PCOS women may have irregular periods
or prolonged cycles. This may be the reason for your missed periods. Your old pattern of prolonged cycles may have returned back when you stopped using the patch.
You may do a blood pregnancy
test to resolve your doubts about being pregnant.Diarrhea
& vomiting is not likely to be related to this period problem. This may represent an attack of gastroenteritis
. You should take lots of fluid & see a doctor for further treatment if this continues.
Wish you good health.