i was like you, when i first went on microgynon 30 i started getting mild period-like pains, but they went away pretty quick. after the first or second month, anyway. i assume you'll have a month check up, so just tell your GP at that point just incase it's anything to worry about (doubtful).
as for mood swings, i don't think i had any on this pill, but i've never been bad for those at all. but yes... my previous advice works for this too.