I have not had a bowl movement in well over a week.i have taken miralax (polyethylene glycol) and even used an enema.i feel a little nauseous.what should i do now?

Get to an ER: Without knowing anything about you; i would insist you seek emergent care now.

Obstipation?: Normal bowel frequency varies from 1 every 3-4 days to 3-4 movements per day. Many "normal" people alternate their stool pattern within this range. What you describe is outside the range, but your prior baseline stool pattern defines how alarming (or not)your current infrequency may be. Ileus, blockage, ischemia is considered if fever, tenderness, distension, bleeding, vomiting. Get checked/help.