R.T.
I know that can be very frustrating. I have a six month old too. Her naps are not always consistent, but she usually does take three a day. If she sleeps less than an hour, I usually leave her in her crib until the hour is up whether she goes back to sleep or not. I wonder if your son might be getting enough sleep and simply wakes because he is rested. How long is he staying up? Maybe he needs to take a nap after staying up a shorter amount of time. My daughter can only stay awake for 1.5-2 hours at a time. If I keep her up longer than that she gets over tired and really fights her nap. I'm sorry you are struggling and I hope it gets better.