I have a iphone5, the battery?

I got it in september iphone5.
when during beginning of oct, i turn off my phone cause i felt like it. And than my battert was save up to 100% i was kinda confuse cause i had like 95%. NOW WHEN I TURN ON MY PHONE, MY PHONE LOSE BATTERY… I'm LIKE i ruin my phone D:. During when i have my phone on the battery is still save it when its 7:44 and go to 7:50 yeah my battery is still the same!
Can you answer me soon as possible?

It ruins a cell phone battery to charge it to 100% or over. To prevent damage to the battery, the charging circuit may only charge it to 90%. If it told the end user that it was charged to 90%, the user might get confused. Instead, the phone reports the charge at 100% when it is close. Sometimes it will bounce around to 95% or 90%. If you have a problem with the battery draining super fast, I would take it to the Apple store.