@blue99 Welcome to Mayo Connect. You will find we are a very diverse group of people! However, we cannot diagnose medical issues, nor can we advise. We do offer support, and talk about our own experiences and what has worked, or not worked, for us.
Like you, I retired in my early 60's mostly due to medical issues. I had been working full time for over 45 years, and it was quite a shock to wake up that first workday and not head out to my job. I had placed a lot of my energy and my social contacts within that job! It took me about 4 months, as I transitioned to "retired", to get my house cleaned up and rearranged, deciding what project I wanted to do. I took stock of what my skillset is and found that I wanted to volunteer [where I could say "no" if I wanted!] and work part time. Yes, I sought out therapy to help me sort through things, and am glad I did. Like you, I have been diagnosed with clinical depression a couple of times.
Honesty is critical. Talk to your doctor, and see what their thoughts are re medication and/or therapy of some sort. Journal what you are feeling, just to get it out of your head if nothing else. Get a complete physical to rule out any organic causes of the way you feel. Reach out and think about things you would like to try or learn, or get involved again in things you used to do. Get outside for fresh air and exercise when you can [this is so healing!].
Please be gentle on yourself, and continue here. If you had a blank slate for a week, what would you do that would be exciting to look forward to?