my battery is running low so fast! plz help

Hello,

See this:

1) Have you tried a restart?  If not, do it now.

2) See the section "View battery usage information" in the link below to see the apps that are consuming your battery:

Maximizing Battery Life and Lifespan

3) Check “Battery Health” in the link: 

iPhone Battery and Performance

4) If all else fails, consider a battery replacement:

iPhone Battery & Power Repair

Good luck.