What contarceptive pill to take?

i have bn told by many ppl that levelin ed is the contraceptive pill to be on at my age. Im 26 and have bn on norimin 1 for about 10 years!!! Is it possible i am retaining weight because of my pill? i had a friend recently change pills from normin to levelin and lose 17 kilos no effort at all!!! should i change to do the same? My doctor gives me no information pro or cons