Since you have had a bad experience with Lupron, I can understand your concerns and hesitation!
However, your body has changed in the last few years and using add-back therapy might be the key that allows the Lupron to be successful for you. You could also get the monthly injection rather than the 3 month one. Other options might include Depo Provera or an aromatase inhibitor.
While both Lupron and continuous birth control pills can be used to stop periods, they work differently and treat endometriosis differently.
The bcp works by suppressing menustration and inhibiting growth of endometriosis, thus hopefully alleviating the endo pain. The continuous bcp's are usually combination pills (some type of estrogen with some type of progesterone) so you would still be getting some estrogen.
Lupron is a GnRH agonists that works by stopping the production of estrogen completely. The goal is to deprive any endometriosis of estrogen in the hopes it will dry up and disappear. With Lupron, there should be no estrogen to keep fueling the endoometriosis.
You can read more about the various endo treatments here: http://www.endometriosis.org/treatment.html
Have you had a second opinion about what might be best for you at this time? What type of doctor are you seeing?
Knowing the best way to treat endometriosis can be very difficult as we will each react differently to each treatment. No two of us have the exact same body chemistry so no two of us will have the exact same outcome.
I wish you the best as you work through all the pros and cons for you to determine which path is right for you!