I first developed Rheumatoid Arthritis 40 years ago in my late 30s. I also have osteoarthritis.
Firstly I would suggest that you get a proper diagnosis, “probably” isn’t good enough. Ask to be referred to an occupational therapist and a physiotherapist, both of whom should be able to advise you on ways of making your day to day life a little easier. The correct exercises are essential. As Kate54 says, you may find it comes and goes, but I was strongly advised that during a “fallow” period I should not put extra strain on my joints which might damage them.
In my case, it was only when my knuckle joints began to swell that others really noticed that something was wrong. I know that this is probably not what you want to hear, but I found that the only people who really understand arthritis are those who have experienced it.
I think you will have to come to terms with it yourself and accept that whereas others sympathise with a short term illness, quite often something long term, and often relatively invisible is forgotten after a while. Many think of it as a “bit of arthritis that people get as they are getting older”, and do not realise the pain and limitations that it brings.
As for helping people etc, I should drop into casual conversation that unfortunately as a result of your recent diagnosis you will have to limit/give up some of the activities you have previously enjoyed. Don’t announce it as doom and gloom, just a firm statement of fact.
I hope this hasn’t sounded too harsh, but as you can imagine, over the years, including operations on hands, feet and elbows, I have experienced most scenarios! Good luck.