Why does my heat get cool when I'm at a stop light

What is your question?

It doesn't happen all the time on and off for two years the car never runs hot it has over 150,00o miles on it last week I was low on my oil 2 quarts that has never happened I usually have my oiled changed professionally but have not in the last 6 months

What makes this problem better or worse?

When the car is moving it gets hot again

How long has your 2005 Toyota Camry had this problem?

On and off for about 2. Years