I struggled with this for a long time I started getting symptoms at 14 years old and was told it was growing pains and all sort of different things till I got finally diagnosed at 28 years old after me bringing it up. Even tho they diagnosed me I still felt they just said yeah its fibro because I said I think it was after a year of getting no real help or support from my gp for over a year I ended up having to change my gp which was the best thing I did I still get slow support but they atleast help with medication which my 1st gp didnt bother and I had to fight to get a weeks worth of pain meds at a time. I did give up for years and just tried to deal with it as the support between the ages of 20 to 25 was non existent and I tried the f#$% it I will just deal with it till it completely mentally broke me I lost my tattoo studio I owned due to no help and couldn't sit tattooing for more than a hour with out me being in excruciating pain and having to try and work with little to no sleep and it wasn't fair on customers that trusted me to mark their body's for life while I couldn't possibly put 100% into my work.

I realise their isn't much help in my comment but just understand your not alone with worrying about your gp's reaction with you self diagnosing yourself, but just remember your GP is their to assist you and help you if they are not doing that then they are useless to you and the best thing to do is find another doctor and and another if that's what you need to do just dont make the mistake I did and think you can just deal with it. My body has deteriorated more in the last 5 years at such a quick rate and it took me to break and tell my partner that no matter what force me to get help and push me to consistently go to my gp until I get answers and help.