Hi afternoontea
I had digestive problems for years very similar to what you're describing starting at about the same age as you are now. Healthy diet and lifestyle, but the gurgling (husband used to call me Froggy), the bloating, the stomach pains and nausea. On a good phase it would wake me at night, and last til about midday and then settle down a bit for a while, on a bad phase pretty much constant. All the usual investigations and nothing found, all the usual prescriptions and otc remedies but nothing really helped much. Gave up in the end trying to work out why.
More than once i asked gp if it could be hormone related and each time "are your periods still regular? - yes they are - well then it's nothing to do with hormones" But i also asked the practice nurse and she said the opposite, and that if i told the gp i was having hot flushes i'd be allowed to try HRT. A couple of years after that my periods changed and the hot flushes and other meno stuff started up, but at the same time the digestive stuff all settled down to almost nothing. Hell of a coincidence if it wasn't hormone related.
Not much i can suggest to help with symptoms, except maybe try regular grazing instead of normal sized meals, and to keep well hydrated. And although it's not for me to suggest that you lie to your gp, all i will say is that i really wish i had done that. I could have saved myself a couple of years of feeling bad.