Would my fibromyalgia be worse if I did not take paroxetine?

Depends. For some patients meds in that class can help but there are other meds that may work better. There are also many non- prescription interventions that can be helpful. In order to develop the best Biomedical plan a full evaluation looking at the immune and endocrine system and nutritional status should be done as these are usually playing a role in the chronic symptoms seen in this disorder. .
It depends. It depends on whether or not that particular medication is helping you with this condition. While there is not great proof that Paroxetine is effective for the symptoms of fibromyalgia, some patients do experience relief by taking it. The only way to know would be to wean off the medication but you would need to speak with your prescribing doctor about it first.