Microgynon and Rigevidon have the same active ingredients, so assuming you got the same dosage pill (both have a few different dosages) you actually were just given a generic of your usual brand and not a new pill. The only difference is the inactive ingredients (to keep the pill stable for storage and shelf life, ensure it’s broken down in the stomach as intended etc). Gederal 20/150 has the same active ingredients as both of the other brands, just a slightly lower oestrogen dosage. Definitely give your body at least 3 months to fully adjust to this new dose.
I would suggest looking into other causes for your migraines, suddenly getting regular headaches and migraines definitely is worth getting checked out