Although they claim to not have any difference, I was on Yasmin (brand name) for a while and then was switched too
Ocella (Generic) and I did notice slight changes in my period. In fact, I never missed a single period on Yasmin, but did miss one while on Ocella. The blue veins, I mean if your fair skin like me, I notice the veins all the time. Sometimes they are bluer then normal, but you can't always go by that being a symptom of pregnancy.