Machair - hang in there. I also got M.E after a virus and was virtually bed bound for 4 years. I lost count of how many specialists I saw, none of whom could help (other than with moral support in the case of one wonderful elderly doc). I believe it is distinct from fibromyalgia as the latter developed later on - similar and linked, but distinct. I have always had the symptoms you mention, as well as (intermittent) gland pain and sore throats from the M.E and chronic, very severe insomnia only from when the fibro developed (with its own usual muscle issues). I first became ill in 1988. Stabilised with flare ups now, more this year. In the 80s, doctors thought M.E was hysteria/depression/anxiety. Luckily that has changed for the better by now.
I do feel age/hormones have made things far worse and I aged more in the last 2-3 years than I would have without M.E/fibro.
I have about 3 - 5 good hours most days and the rest of the time I have to rest. I look fine if a bit tired, and am only mid 50s so not being able to work causes me distress.
Some people are far worse than I am, and of course no-one gets any disability benefits any more.
PS I think there's a link with glandular fever too. I had that at 12 years of age and believe it never really "left".