Peach8, No, I'm not on the POP any longer - although I could have stayed on that as well as being on HRT, but the desogestrel isn't approved as a progestin for HRT purposes. (There are a few small trials where it has been used at double the POP dose for HRT and it's been fine, and there are some women who are just on a single dose for HRT purposes with scans occasionally to check lining is ok.)
Instead, I'm just on a higher than usual dose of utrogestan to suppress the endo whilst I take estrogen - and it seems to be working fine. Dr Prior has done a lot of work into using body identical utrogestan instead of synthetic progestins for endo:
https://www.cemcor.ubc.ca/ask/endometriosis-and-natural-progesteroneI wish I'd known about all that before because I'd rather have been on utrogestan than desogestrel. I was told point blank by 2 GPs 'there is no way utrogestan will be enough to suppress your endo, you'll need to get a Mirena'. They wouldn't give me HRT unless I had a Mirena. But I didn't want a Mirena unless it was my last option, I wanted to try utrogestan first. So I went private and got utrogestan and it's been great. I am very tolerant of progesterone though, and can take as much as anyone wants to give me.
You could look into getting a laparoscopy for your endo. The gold standard is excision surgery. If you're on FB, there are some good endo groups. There's Nancy's Nook and a few others. They have lists of surgeons who do excision. With excision, they cut out the endo from the roots so it can't grow back and it's much more effective. I didn't know about that when I had my lap, and I just had it lasered out. I think mine is mostly under control with copious progesterone now. There have been a few moments on HRT when I wasn't on such a high dose of progesterone and the pains came back. Within one cycle I got rid of them with more progesterone. My lap surgery found just a few small patches of it, no adhesions or major endo. But often with endo the pain isn't correlated with the severity of endo. There are people with no pain who are found to have extensive endo when they have surgery for some other reason. And there are people with intense pain but the endo is very mild, like mine.
And yes, before I was diagnosed with endo 12 years ago, I would throw up and pass out the first day or two of my period. I have not experienced pain like it. I was literally out of my mind with the pain, writhing around on the bed during these attacks. I think I'd pass out to get away from the pain. I found that naproxen was the best pain killer for this and if I took it as soon as I got my period, without waiting for any pain, and if I took it the whole first two days, I was pain-free. This lasted for several years and I thought I had it sorted. Until I started to get pains outside my period as well... But if you haven't tried naproxen yet you might want to give it a go. You can get it over the counter in the USA but in the UK I think it's not as available, but there are one or two period pain meds with it and your GP can prescribe it.