Hello and welcome. I'm soooo sorry about your diagnosis - it' such a hard blow to have your body 'fail' you, I know.
I'm 39 and was diagnosed about 5 years ago with rheumatoid arthritis (and IBS; initially it was assumed I had Crohn's disease because of my overall symptoms). My understanding is that PA is very much like RA, with added skin issues.
I went primal almost 4 years ago. My results have been nothing short of life changing!! I was considering that I might have to go on disability (and I was involved in sports all of my life previously); now I am doing all of the sports I was involved in before and I have an active life with minimal impact from RA! Of course, I still have 'bad' days, but believe me when I tell you that my 'bad' days now are what every single day was like before I went primal!!
However, it took quite a while for significant changes in joint pain/swelling to appear. Initially, I only noted that if I 'cheated' by eating anything with grains or SUGAR it would INCREASE my pain and swelling the following day; it took about six months of being strictly primal before I began to notice big improvements in joint pain/swelling. (Boy, pain will change your thought process when it comes to 'cheating'.) I did have an improvement in fatigue and IBS within a week of going primal.
I'll reiterate what others have said about the importance of vit D and strict primal eating. Another huge factor for me has been weight lifting; I believe that the combination of increasing blood flow and strengthening muscles/tendons is key to keeping and improving joint function and mobility. I don't do any 'isolation' lifts, only full range of movement lifts (ie. squats, overhead presses, etc - in other words, follow Mark's suggestions) Start slow, and if you're not familiar with weight lifting, get help from a fitness trainer to make sure you are performing lifts correctly, since you can hurt yourself with improper form. For me, initially, the weight lifting was not comfortable, but I would notice improvement the following day in my mobility, and, like with the sugar/grain, I noted that skipping several work outs in a row would cause an increase in my joint pain. Four years down the road, I'm lifting about 3 times the weight I started with, and it feels GOOD to push my body - I look forward to my work outs!
I also agree that you should pursue the medical route; RA (and I assume PA) can cause joint damage, and you want to prevent/slow that damage. My insurance made me do a 'trial' with methotrexate before I could go to the more expensive biologics (I'm on Enbrel). Currently, I take NSAIDs (this year I was able to cut to 1/2 the total amount I was previously using) and Enbrel only. Additionally, I take fish oil, vit E, vit D and probiotics (I take the probiotics one week on, one week off, and that seems to work well for me). I'll also totally plug Mark's Primal Calm as an excellent stress management tool.
Oh, and I had put on a lot of weight initially with dropping all the sports because of RA - now, my body looks better than it did in my 20's!!
Wow, I've been long winded, but going primal changed my life! Hmm, guess I need to get off my butt and write in to Mark's 'Success Stories' like I keep saying I will!
I hope it helps to know that others here have gone down your road, and that there is hope!
A ship in harbor is safe - but that is not what ships are for. ~John A. Shedd