Would adding a diet pill harm me with the meds i'm already on as i had a hysto last year and since then can't lose the weight i gained? i have fibro.

Depends: It really depends on what other medications you take. Your profile indicates you take Xanax (alprazolam) and have a history of heart failure and atrial fibrillation. Some of the more common medications and herbals used as 'diet pills" may worsen anxiety and increase heart rate. I think you should consult your cardiologist before adding any "diet pills".