Iphone is lagging

I’ve iphone SE and uts lagging even after i updated it to ios 11.2 ... its lag when i make calls or swipe down the notification panel... its annoying me... 12.4 gb left in storage... and i only install some apps i.e whatsapp, messenger, facebook, twitter, snapchat, clash of clans, nfs no limits, retrica, amazon, paytm, shareit, truecaller, my airtel app, google translate, Google App, Gmail, youtube and instagram... please help me