Little sensation, lose of physical desire but plenty of mental desire...any recommendations to help?

I just turned 49 and this began about a year ago, I believed when I started taking Anti Depressants. In my head, I would be ready to go as usual, but my body felt like it could care less. Its almost like I am dead below the waist and have to take Viagra to maintain an erection, even then sometimes its just no go. I quit taking the Anti Depressants a few months later and have been off them for about 7 months or so, but still no interest below the waist. Did I watch too much porn, masturbate too much? I also used to ejaculate fairly easy, almost to a fault sometimes. Now, I have to visualize things just so I can. What is wrong with me?

Thank you for your help in advance.