first periods on BC?

I had my first period on birth control and it made my PMS %150 worse I couldn't even handle life, also causing awful painful cramps I've never had, and my period had no difference other than a little old blood that drifted on for four days after the actual period ended. So how many months will it take to adjust? Do the symptoms get better? I'm to scared to try another brand as several others caused bad reactions such as nausea and vomiting. I should also add I have extremely heavy periods that span 9 days 😬 so I've also been put on iron to control that