Hey K.. Your doctor should have given you a brochure on the Mirena. If he/she did not, be sure to ask for one. While on the Mirena it is very common to not have a period. This is caused by the increased amount of progesterone in your body. The increased amount can in some cases stop the release of the egg, therefore, causing your body not to go through a menstral cycle. Some common side effects include: Cramps, dizziness, or faintness. Other more serious side effects include: Pelvic Inflammatory Disease (which requires an antibiotic treatment), Preforation (going through the uterus), or expulsion.
I am confused as to why you have to wait to see your ob/gyn. When I was having problems with my I.U.D. (Severe cramping, muscle spasms, fatigue, headaches, and endometritis) my doctor got me in right away and had it taken out that same day. Which, by the way, doesn't hurt at all even though some women say they feel severe pain. I was on POP's that very next day.
About the nausea: It is also due to the increased amount of progesterone. Once you start your new birth control I highly suggest eating a banana or some other form of high protein snack with it and take it in the evening before bed. The chances of nausea should go down. Also, headaches and migraines are common with many forms of birth control.
When you call the doctor's office again (which I highly suggest), tell the receptionist that it is imperative that you speak with a nurse or doctor. While the receptionist is in that profession, she does not have a degree in Medicine and should not be telling you to disregard your symptoms as far as your birth control is concerned!
Sincerely,
M.