Iphone notification bar freeze ios 8.3

i've been experiencing lots of trouble when i updated my iphone 4s into ios 8.3

first

My notification back freeze half way of my screen and i can't turn it back until i switch it of.

Second

i cannot see any of my notifications in the home. I dont know if i already have reply on any of my messaging app. I need to go to the app every single time just to check if i have already a reply or something. It also happens in facebook, instagram , twitter.

Last

my wifi always disconnect. I nee to turn it on every 10 mins or so

Please how can i fix this. Its really getting troublesome