I am losing my finger nails, they are cracking and breaking off, especially my thumb nails. Any help

Well, it goes without saying that you should discuss this with your rheumatologist. Nails are a huge headache for us. Many of us with PsA also have hypothyroidism, which itself will cause brittle nails. And hypothyroidism will exacerbate your PsA symptoms, as well as having unrelated symptoms itself. Have you had your thyroid functions checked as of late?