I hope you're feeling better soon.
My experience with PsA has been that it is totally unpredictable. I'll give you an example. Months ago, I had to go drug free because of liver problems. No MTX, no tylenol, no diclofenac. All I was allowed was 2 naproxen per day. I thought I'd be in huge trouble. In fact, I felt great for about three weeks. I started to ask myself why I had been taking all these drugs in the first place. Then after a few weeks of bliss, I had a massive psoriasis flare (and my first ever diagnosis of the pustular form of psoriasis) followed by terrible joint pain and swelling. Then I started Humira and I felt better in one week. Then I got sick again despite the Humira. Now I feel pretty good.
My rheumatologist and my dermatologist have both told me the same thing: that my symptoms flare and subside. And that the DMARDs can reduce the frequency and severity of the flares, but may or may not stop them. And that the improvement after one Humira shot was a coincidence.
So perhaps your dosing schedule caused your current woes, or perhaps it didn't. For me, it's unknowable, and this uncertainty is very hard. I actually wake up in the middle of the night sometimes and try to figure out how bad my joints are going to feel the next day. At least with the Humira I feel like I'm doing everything I can to make it better.
Healing well with psoriasis, PsA, and hypogonadism, and happy to share my experiences.