So are you just looking for a diagnosis then? Because I don’t think people are trying to be unkind even though you’re losing patience with all the people mentioning coils, but have you researched the treatment for endometriosis, OP? As others have tried to point out, very gently, the medical options ARE forms of birth control, such as the coil (that’s what Mirena is, as one person mentioned), or other things that would stop someone TTC, like hormone therapy. Besides those, the other options are surgical and 1. They’re very unlikely to approve those before you’ve tried any medical options, 2. Surgical options will either stop you TTC or not be an option if you’re pregnant, and 3. If your endometriosis is that advanced, causing constant pain, missed periods, if there are adhesions to your bowel or other organs, etc, the NHS’ surgical recommendation may be a hysterectomy. If you have specific endometriomas that are blocking your ability to become pregnant, they MIGHT consider surgery for those. Otherwise, they will most likely spout out the line that “most” women with “mild” to “moderate”* endo get pregnant naturally (though from what I’ve seen, it can take a lot longer, and I know that can be heartbreaking to deal with every month), so if you want to TTC, you may be left with no endo treatment. I’m sorry you’re dealing with this; I’m sure it feels incredibly unfair that you may have to face these choices (constant pain or stop TTC), and I really do hope they can find a solution for you.
*Please note that I’m using mild to moderate as medical terms. There is no real “mild” endo, IMO. It almost always affects a woman’s life in the form of pain. By mild, doctors mean there is less ‘out of bounds’ tissue growth.