Everyone's hormone balances are different and react differently to 1) the balance of estrogen and progesterone and 2) the type of hormones, especially the type of progesterone.
For example, some people's hormones are already well - balanced on their own and can "adapt" to different 'mixes' , others are awful on estrogen (a few of my friends) and others NEED the estrogen and are awful with just progesterone or an androgenic type of progesterone.
It's the 'base level' of your body's own hormones which determine the effects of different hormonal contraceptives. This is why sometimes a woman will resume a contraceptive which suited her for years pre-children but after birth she gets awful side effects, because her hormone balance has changed.
Personally I have PCOS too and I definitely feel much much better with estrogen added, my mood lifts like your OP and I feel a sense of 'well being'. Too much progesterone or an androgenic progesterone (Microgynon) or - heaven forbid - progesterone on it's own! (Cerazette) - I am a spotty, greasy, morbid depressed and bloated mess
, but too strong an estrogen (Cilest, Dianette) I get all the good side effects but sadly I get estrogen headaches on them, so settled with Mercilon (smaller dose estrogen and non-androgenic progesterone).
IMO, GPs are awful at just not giving a damn about the side effects for the women or bothered about researching which balances work best for which concerns or side effects, they often say "they are all the same (pills)" , which is utter B.S. At times I have felt like a baby-making-machine they are determined to give anything to (particularly anything cheap) , just so I don't have an unwanted pregnancy. They would save a lot of consultation time and wasted prescriptions if they just tried to get it right in the first place. If you do some of your own research you can usually work out based on your own symptoms (greasy hair, acne, moods, breakthrough bleeding etc) which type is best to try for you.
OP, glad that Dianette is working for you. Some professionals do not like to keep a patient on Dianette for longer than 6 months to a couple of years however due to slightly increased risks of clot etc with this pill. If this is the case, a switch to Yasmin, Marvelon/Gedarel, Femodene or perhaps Cilest is an idea. For PCOS sufferers ones to AVOID are Microgynon or basically anything with a progesterone other than desogestrel, gestodene, drospirenone, or norgestimate.
xx