Yoga is a nice gentle exercise you can do (there are even specific exercises for pelvic pain), plus you can do it at home using YouTube videos if you need to... and build it up to faster/more intense yoga as you improve.
Diet wise, some people find making diet changes or eliminating certain foods helps, and you often see 'endo diets' mentioned online, however they tend to be a bit inconsistent, and what works for one person might not work for another, so if you are considering cutting out any foods, I'd suggest eliminating one thing at a time and seeing how you do. Everyone is different though. Some women with endometriosis are overweight, but many weigh less than average, some have bowel symptoms that seem to be impacted by diet, and others don't... so it's an individual thing, and you sometimes have to experiment a bit to see what works for you. Eating good food (such as fresh fruit and veg) and avoiding too much junk is always a good idea though, and could help you feel a lot better as you recover from the surgery.
If you are interested in the diet side of things, google endometriosis diet, and you will get lots of results (there is also a nutrition related endo group on fb that should come up if you search on there), but as I said they can vary, so I'd suggest reading through a few to get a good general picture... and maybe be wary of sites that make unlikely claims or insist you will definitely be able to cure yourself entirely with diet. Eating healthier can definitely help though, and diet changes can help with some symptoms (for example if someone has bowel symptoms eliminating certain foods might help them).
You mentioned you had a a cervical erosion cauterised and mirena coil inserted during your surgery, but do you know if they also excised (cut out and removed) the endometriosis? Hopefully they did, and your symptoms will continue to improve (as it can take a while to heal up after surgery and for the mirena to settle down), but if your symptoms continue I'd suggest confirming the disease was excised... as any remaining endometriosis could continue to cause pain and symptoms.