Extreme nausea for 4 months due to several changes in birth control?

I have been having acute nausea since early February 2009. It got to the point that for one particular week, I could barely eat or drink, started shaking and had dry heaves for 4 hours but couldn't puke due to dehydration. Was shaking, couldn't breath, and went to the hospital by ambulance and had an IV put in.

I am 33 years old, 5' 5". My regular weight is 120 lbs, but beginning in February have gone down steadily until I am now 93 lbs. Since February, I have been living on tiny nibbles of soda crackers, small drinks of water, ginger, and pepto bismal any time I have to eat. I feel like I'm starving, but have to eat very little and slowly, or the urge to vomit comes on. After 4 months, I feel weaker each day.

To clarify and hopefully give some possible reasons for the nausea, I will list key events:

October - November 2008-: I was an egg donor at a fertility center, so I was put on birth control, but I forget the brand name. I had no nausea at this time.

December- January 2009: my doctor prescribed me Lutera because it was low dose, and I told her I wasn't used to birth control, since I hadn't been on it before. I had very mild, occasional nausea on Lutera, but barely mild nausea.I thought I'd need to get used to the bc before I had no pain.

February 9, 2009 : I asked my doctor to change me to Yaz because I had acne, and thought it would clear up the acne.Immediately after taking it, I had severe nausea. The nausea continued on, but every 2nd or 3rd day, it would lead to the urge to vomit. In between these urges, there would be a general feeling of nausea.

March 8: I started taking Tramadol, 50 mg 2x a day, for migraines. A total of 100mg each day.Nausea lasting each day.

March 27: Stopped Yaz, since I thought it was causing the nausea.
                Went back to Lutera, since it was a lower dose of estrogen.
                Still taking Tramadol.

March 27- April 7: Nausea more extreme, even on Lutera. Nausea coming on with no warning, even after nibbling.
                           Started Jollivette, a mini pill, since I thought the Lutera was now making me nauseous.
                        

April 7- April 14: took Jollivette, but nausea continued to be extreme, severe nausea after even drinking water.
                        

April 14: stopped Jollivette birth control, completely stopped taking any birth control.

April 14-18: took no birth control, but continued the tramadol. Nausea just as extreme, if not more so. Could not
                 keep even water in my system.

April 18: Decided that a week of nausea without taking birth control meant that the nausea also came from the tramadol? Stopped taking tramadol, cold turkey, even though you are supposed to taper the dose.

April 18- 26: worse nausea than any previous time. Additionally tramadol withdrawel effects of diareha, shaking, tremors, etc. Eating and drinking tapered, became dehydrated.

April 26: Went to ER for dehydration. Got a prescrip. for ondanstron.

May 3: Saw my primary care physician due to continued severe nausea. Almost too nauseas to get to the doctor.
           weighed in at 93 lbs. She gave me a prescrip for ondanstron, also so I can keep in fluids and not get
           dehydrated again. She said to come back in a week if I didn't feel better.

May 3 to present (May 5): Nausea continues, to same severe degree. I am an elementary school teacher, and this morning I ate a half a handful of dry rice krispies. Afterwords I was about to vomit, but didn't want to vomit on the students, and couldn't leave them alone in the class. Took one ondanstron, and was a bit better. However, I am very week, starving, but can't keep in my system what I nibble on.

Basically, the nausea began full force on Feb. 9, 2009 when I started taking Yaz, and has remained constant and severe up until today, May 6. The nausea is moderate, rarely if ever mild. If I don't eat or sip slowly enough, it leads to an urge to vomit. (I have never had an episode of nausea like this before, in my life).

My questions:

1. Since it has been 22 days since being on any kind of birth control, and 17 days since taking any tramadol, should I still be having this extreme nausea?

2. Do you think that switching birth control brands 5 times in 7 months time caused the nausea? Or was it also caused by the tramadol ( I was on Yaz for a full month before taking Tramadol, and had severe nausea before taking the tramadol).

3. How long should I expect the nausea to last before it runs it's course?

4. Could the nausea be due to something else? I've had my period regularly each time I got to the inactive pills, and/or each time I changed the birth control pills. The last period I had started April 9 and ended April 16 (It was long because Jollivette supposedly causes long periods in the beginning.)  I thought maybe the nausea was due to pregnancy, but the nausea has been solid and steady since February 9th.

I thank you for your time. I appreciate any advice and suggestions. Also helpful, I think my body doesn't agree with many medications, in general, except Tylenol. I've had reactions to amoxicillin, penicillin, monocycine, doxycycline (sp?) in the past.  I know this post has been long, and I may have answered my own questions but I value expert advice. I will see my primary care physician this weekend, but she seemed as confused as I was last week when I spoke to her. Again, thank you so much!!

AJ