I Am Having Trembling Inwardly And Now Outwardly. This Started

I am having trembling inwardly and now outwardly. This started years ago only when I would be in bed a couple of hours and went from once a week to now all the time and is lasting all day when it used to go away as soon as I got up and moved around. I have taken diazepam for back pain and it seemed to work on this also before but now if I take a diaZephaniah, 5 mg, as soon as I sit down and doze off, it starts when I wake up. My family doctor is treating this as anxiety and depression but I feel it is causing anxiety and depression. I am 75 years old. Any ideas?