What happened? Riddle me this.

I was a very overweight kid. My whole life, overweight. I graduated high school at 245lbs 5'10", size 20W. When I was 18 I started smoking. I ate one super sized McD meal per day and I lost 45lbs. (I was not intentionally trying to lose weight then.) So I weighed 200, Size 18. Then I started eating my regular way again and I gained to 225lbs. Size 18/20W. When I was 21 I made a decision to get healthy. So I started my path. I began exercising. I made a routine. I went to the gym for 2 hours EVERY MORNING, 7 days. Rain, sleet, hail, tornado.. I was there.I had a friend who became a personal trainer and she would also work out with me in addition to the 2 hour/morning sessions that I was doing. I was also working 50+ hours at a very busy restaurant. In the morning I would get a chocolate slim and trim no turbinado. During the day I had only one opportunity to eat during the day. I ate: 2 crunchy beef tacos. At night when I got off of work, I would eat a steak fajita plate, or a nachos al carbon (steak nachos.) NO SUGAR. That was it, the end.. every day. I got so advanced in my training that I was running approx. 20 miles a week. I was doing 5000 stair every day. My trainer friend showed me the proper way to work out on the weights and also did many free weight exercises with me. I was doing master's classes! I was so proud. I lost from 225lbs, to 200lbs. I was now wearing a size 16. I needed to lose more. My 'healthy weight' was from 145 to 1 75. So I was ready to go for the goal. One day I finally saw the scale drop to 190. I was there for one week. Then it went up. I went up to 200, and then 210, then 215, and finally ended up right back at 225 WITHOUT gaining a size. The one thing I did add to my routine was pilates. ( Which I loved.) This whole process was from 2001 to 2004. I did this for 3 years. In this time, I learned that I LOVE to exercise. LOVE IT! And that my body sucks. I still had big globulous fat on my inner thighs. That was the ONE area I had focused on and asked my trainer friend to help me with. I did more work trying to rid my thighs of fat than any other thing. My trainer finally told me that it won't budge, and that I probably need plastic surgery. I have told this story a number of times in hopes to find out what happened. After this I had 4 kids in a row, so after that without watching my diet and not exercising (what's not to manage 4 kids under the age of 7, phew!) and I was at 245lbs BUT still at a size 18. So although I went up even 20 more lbs, I still stayed at 18. <SHRUG> I have been told that: I wasn't eating enough. I have been told that my adrenal glands were burnt out by all the exercise. I personally tend to believe that it was the Depo Provera shot that I was on. But it seems that with all that intense work that I should have been able to attain my goal. I am not complaining in any way, just looking for some answers as to not have a repeat. So far I started MFP about ONE WEEK ago, and just watching my calories I have lost 12 lbs. :huh:
So I am wondering if anyone had any ideas. After my 3rd child, I did go to a natreopath who told me that I had a thyroid issue and gave me some meds that I took and I finished. I was having severe memory problems, and my body temp was hitting 94. I was becoming narcoleptic. His meds WORKED (although they were freaking nasty tasting!!)