My dog has a serious whining problem when it comes to being fed and any time he gets a glimpse of me through our sliding glass door. Is this separation anxiety?

My 4 month old rottie might have picked up on his feeding schedule. He tends to make a big fuss 1/2 hour before feedings. Is there something I can do to have him wait patiently until feeding? He'll start whining non stop until I come out with his food bowl.

Actually, another problem we're having is that anytime he catches the slightest glimpse of me he starts to whine. Last weekend I stepped outside to get something from our outdoor fridge at about 12:30 am. He started whining nonstop until about 3 am. I think he only stopped because my mom went out to see what was wrong. He'll whine and whine and the minute I step outside he is quiet. He waits until I let him out or until I go back into the house. It has gotten to the point where I have to avoid walking past our glass door so he doesn't start crying.

Is this separation anxiety and is there a way for me to end it?

Thanks,
Collin