Dear M.,
I want to encourage you to hang in there with nursing as you wrestle with this issue. One thing I've noticed about nursing (three boys now - nursed til 2 years old) is that it is very helpful for getting the weight off, but not usually in the first year. I would usually hit a point somewhere between 12 to 15 mos when a chunk of weight would come off. Here are some articles regarding nursing & dieting, as well - http://www.kellymom.com/nutrition/mom/mom-weightloss.html
Also, I want to offer a great alternative for you to try - acupuncture. Our family uses it for just about everything, and the results are fabulous. Dozens of my friends have gone on my recommendation, and the stories I could tell you would surprise you. It is not painful (it's actually incredibly relaxing, like getting an hour massage). The fabulous thing about it is that it gets to the root problem, rather than treating symptoms. Whether it's a thyroid, hormonal or even an addictive issue, acupuncture would help.
We love going to the clinic at the Acupuncture College here in Houston - http://www.acaom.edu/en/cms/?42 - it is located inside Beltway 8, just off Westheimer. The great thing about it is that the care is fabulous - you get 4th year students working under a professor's guidance - AND the prices are great. It's about $35 per treatment, and I believe every 4th visit is free.
Also, consider joining some kind of a support group. I'm sure that would help a lot - just to receive regular encouragement and accountability.
There are a couple of classes being offered now at my church that could offer support regarding weight loss. The church is in NW Houston, so I don't know if that's convenient. Anyway, it's West Houston Church of Christ - ###-###-#### http://www.westhoustonchurch.org/
I pray you find the support you need!
Blessings,
R.