I have had RA probably since I was 15 and like you was fobbed of many times in the UK and never diagnosed or taken seriously. I was diagnosed aged 31 in Spain (where I have now lived for many years), the first time I went to the doctor when having a flare. I was given Prednisone and naproxen for about a month while they ran the necessary tests to check my suitability for a biologic, and then they gave me a biologic and other than the very occasional minor flare after having an infection that means I can't take the biological I have been in remission ever since, that is, practically no pain, no morning stiffness, leading a normal life. Had a third child etc etc.
When I went to the doctor in Spain they ran bloods and found my CRP levels to be sky high and rheumatoid factor of 147. I was unable to dress myself, could lift my arms above my head to tie back my hair, could not walk without a stick, thought I was going to have to sell my flat and move because I live in an apartment without a lift.
After taking the biologic I was fortunate enough to have a great result.
Now my CPR levels are in normal range and RA Factor about 11 (in normal range).
There is hope of living well with this disease.
I have never taken methotrexate or any of the old fashioned medicines and they were never suggested to me here in Spain.
Push very hard and don't allow them to fob you off. The NHS is a bit shit, you need to advocate for yourself. They can prescribe biologics but they usually want to try people on methotrexate first .
Look up the cost of methotrexate Vs the cost of biologics and you will see why.
Best of luck, it doesn't mean your life is ruined. I remember feeling how you are feeling.....and now I am (thank god) leading basically a normal life. I am 40.