Feet turning purple when sitting even just a few minutes. heavy almost numb sensation, so no pain. it goes away if i walk around. returns when sitting/standing still. should i see primary care or a specialist? if so, which specialist?

You should start with a primary care doctor first and an internist (an adult medicine specialist) is preferred.

What comes to mind is a vascular problem, more likely the venous system (as opposed to the arteries). I say this because muscle use when walking tends to help push venous blood back up towards the heart. Arterial disease more commonly gives you pain and cramping when walking. The valves of leg veins may be incompetent which may let venous blood pool in feet. A vascular surgeon may be helpful.