I personally would go w/the suppositories. You don't know how much you're getting in regards of the amount of progesterone in the cream and if it's enough or too much since it's not monitored by the FDA.
I can understand about the mood swings and wanting to go to something more natural - what does your doctor say?
I've been taking natural progesterone (Progon B pellets,by Bezwecken) for the last 10 months and I've also tried their cream. For myself, I found that the pellets, which I let completely dissolve under my tongue works alot better than the cream to increase my progesterone levels. I've never had any side effects from this product and will continue to take it two weeks out of every month. God Bless.