Thank you for the query.
Definitely you should go to the ER. It might not be a regular constipation
but intestines obstruction due to some large intestine pathology. Especially if you do suffer from nausea, bloating, weakness, had recently lost some weight or have had blood in stool
Such condition can be caused by abdominal adhesions
, inflammatory intestinal disease
or colon cancer.
You should have abdominal ultrasound, full blood work and colonoscopy performed.
Hope this will help.