I have mctd (+ana, rnp). Recent test when I was unwell + anti ro, sm/rnp, anti smooth muscle, antichromatin-low titres of most. What does all this mean? Is my disease progressive? I am terrified.

Dietary modification. Consult a comlementary dietitian or md to modify this.Very little remedy in western medicine.
See below. In order to interpret these tests, you have to interpret them in context with symptoms and exam and other lab results. Sometimes these can be false positives. I have to recommend that you discuss with doctor since I do not know all details to determine whether you have progressed or not.