Rheumatoid Arthritis Treatment

Especially when the diagnosis comes at 45 years of age, with no previous history of mental illness?
My apologies for the lengthy additional details, but this is important. Here is a brief summary of what has happened in the past 4 years:
Single mom with rheumatoid arthritis, a painful, crippling disease.
Widespread osteoarthritis, in need of two total knee replacements, various other joint reconstruction necessary.
No pain meds nor pain management prescribed by doctors.
Currently taking moderate, fluctuating doses of prednisone along with 20 mgs. of methotrexate (a cancer drug) weekly.
Feelings of guilt over how this disease has affected my family.
Inability to engage in many previously enjoyed activities. This has led to a sense of loss.
Mother has been ill during this time and has endured 5 surgeries.
In the past 90 days the following has occurred:
Found a breast lump with lymph node swelling in the nearest armpit.
Enlarged thyroid with thyroid lump.
Have entered menopause.
Monthly income has dropped by more than half, with total income per month at less than $400 dollars. Very real possibility of homelessness.
Strange medical and emotional symptoms include panic attacks, night sweats, extreme fatigue, insomnia, irritability, frequent crying, increased joint and muscle pain, etc.
Feeling depressed and overwhelmed, I sought counseling. My therapist felt I was simply overly anxious and depressed, and recommended that I speak with the clinic psychiatrist. She felt he may prescribe something to ease my symptoms.
After only one hour with me, during which he asked only 10-15 questions to which I was not allowed to elaborate in my answer, he slapped me with a diagnosis of bipolar disorder, wrote a prescription for anti-convulsants and sent me from his office.
Needless to say, this has caused additional stress, and I will be seeking a second opinion.
My question is, considering all that I have endured these past 4 years, is it possible that the diagnosis is grossly inaccurate?
Might one in my position be expected to suffer anxiety and depression, and experience similar physical and emotional symptoms?
Thank you for taking the time to read that.