Right, so obviously this is not normal and needs to be sorted. Quite frankly your GP is shit, knows you are in pain and won't prescribe meds. Your consultant should have prescribed you meds and then sent a letter telling him to continue prescribing.
My own story -
I had horrific painful periods from 12. Told I was a wuss, suck it up, blah blah blah, (even from my own mother) they put me on the pill at 16 which helped but it was still very painful. Over the counter meds didn't touch it. I was prescribed Ponstan at some point. Anyway, long story short I had very high blood pressure and aura migraines so they took me off the pill permanently. Symptoms came back.
Saw a female GP who suggested endo, referred me to consultant. Condensed this is how it went and we moved onto the next stage each time
Pure progesterone - Dydrogesterone (Duphaston)
Chemical menopause - Nafarelin (Synarel) aka GnRh analogues, plus HRT for osteoporosis for 6 months.
Laser lap & dye surgery for actual diagnosis but also treatment and to check if my tubes were clear inside.
Told it was a fucking mess inside with scar tissue (no shit Sherlock) told I would need IVF to have children. I was 28 and married for 3 years, with a full time job. Next step was mini pill for 3 months whilst my body settled down. Saw him again, he said it was all back and I had an aggressive type.
Basically he said try for a baby, it won't happen and then we can put you on Chlomid to make you release more eggs in 6 months and start the IVF route at 12 months. I was pregnant 2 weeks later
that shocker miracle pregnancy is now an almost 18 year old. And that tells you how long ago it was and how little it has moved on in terms of treatment.
I did end up giving up working due to the fatigue around the time Ds1 was a toddler, PIP is almost impossible to get for endo I believe. I will say that being able to listen to my body, sleep when I need to (every fucking day, and no I don't enjoy it, it spoils holidays, weekends away, visiting friends, going out for the day with friends) I get to just potter around. I have been a SAHM for 16 years. I have a very supportive and understanding husband.
I currently use a TENs machine for my periods plus Migraleve Pink, for the anti-sickness med in it and the small 8mg dose of Codeine right when it all starts. I also have 30/500mg co-codamol but tend to only take that at night as it makes me a zombie. I hate the feeling.
I had 2 C sections so a coil would be more difficult for me but I would think about the coil with the hormone for you. My mate had that and massively relieved all her endo symptoms.