LOST MY BIRTH CONTROL

Need some help rn. I went skiing and lost my birth control in my ski bag! No where to be found. So I called my normal pharmacy and they said they wouldn't have it for a couple days!! So I called another pharmacy. They had the same brand but different number of pills. So Larin 21 is the birth control I usually take. But....my pharmacy didn't have them....but another pharmacy has Larin 28 which is the 21 active pills and 7 iron pills. I'm wondering if anyone knows the difference? Is it still the same brand??? Need some help.