Quoting Dagny: KAW, the cycle how I see it, is he gets in this grumpy/stone mood where when he comes home he will shoot looks at me and doesn't come near me to say hello/hug. I get the, oh no, something is wrong feeling in my stomach and begin to get upset--what is wrong, is it me (if it is work he will usually share it), then I feel I need to cheer him up, and ask what is wrong, and start feeling like the whole relationship is going downhill.
OK, so maybe a little tweeking is needed. Can you have a anecdote of the highlight of your day ready by the time he comes home? "A funny/interesting/weird thing happen to me today..." ... there by trying to lighten the mood ... then ask "How was your day?" rather than leading with a negative question like "Is there something wrong?" Act "as-if" your PMA and upbeat conversation can shake off his mood. If it works, and he lightens up, you will have your reassurances without having to ask for them.
Quoting Dagny: When he is like this, I start needing things more from him--hugs, conversation, I don't get it, I get grumpy and thus the cycle.
You're taking his mood personally and thereby getting sucked into it. Just because he has a hair up his butt doesn't mean that it has anything to do with you. If you want to be supportive and understanding that's great so long as he is receptive to it. If not, leave him alone to wallow ... don't get suck in to his drama and the easiest way to do that is to leave him be.