Mandmsmummy - I had the same symptoms three years ago. The doctors were so convinced that it was MS that I had fortnightly scans for a while, because they couldn't find lesions, and the hospital presented a special case to NICE so that I could start MS drugs without having lesions. I got taught how to inject into my stomach and legs, and the first chemical disposal containers and injections were dropped off.
Then NICE ruled out meds without an accurate scan. By this point, I'd had fortnightly scans for nearly 6 months, and nothing was showing other than the symptoms.
They rescinded the MS diagnosis and replaced it with fibromyalgia. Unfortunately, fibromyalgia is a catch-all diagnosis for when they don't really know what is wrong. It exists, people with it are suffering, but there is no cure. Typically, they prescribe an antidepressant to help with sleeping, and painkillers. I've tried Amitryptilin, citalopram, liquid morphine, morphine patches, gabapentin, lyrica, tramadol, co-codamol, naproxen, and probably various others that I can't remember. I've been seen by the pain clinic, the sleep clinic, neurologists, rheumatologists...
Luckily, my consultant hasn't given up, and I'm now being monitored by a London hospital who are determined to remove the fibromyalgia diagnosis and replace it with the actual issue. I'm glad, because while I like having a diagnosis, it means that whenever I get a new symptom, I'm told it's the fibro and there is nothing they can do.
The tests for MS aren't bad. They may want to repeat it a few times to monitor for changes, dependant on your age, but if you're over 30 than they tend to believe that you'd have visible lesions if you had it. If you do have it, there are really good treatments now. I pass out at vaccinations, but was getting used to practising injecting things. If you vary the injection sites like they teach you, there is no scar tissue. They are very organised at getting you medication and monitoring you, and MS clinics are some of the best organised clinics that I've ever been too. There is a lot of mental support, too.
If you don't, you'll probably find that they do more scans to look for different types of arthritis, which can cause similar symptoms. Then they'll probably tell you it might be fibro, and prescribe any meds that they feel might help. It's a bit of a fight to get these changed, because eventually you hit the top of the painkiller chain, and nothing lower than morphine will work any more. I have a morphine drip every now and again, but to get to this point was a fight.
Don't worry. There are days when I wish it had been MS, so that I knew what to expect and would get support and treatment. Either way, though, you'll be okay.
(As an aside, I had a lot more symptoms than you've listed - my body is physically ruined by my mum taking abortion tablets regularly during pregnancy. Your experience will probably be a lot better than mine!)