My screen is scrambling ad glitching and mixing all up some of the s

My s5 screen glitches out so bad it mixes up the screen .. sends the key pad up the to the top. Scrambles word and some wierd squares start to look like snow on a TV that is on a bad channel please please help I'm on disability and I can't afford a new phone itvwas find when I got it a month ago from a friend I've never dropped it I'm scared I won't have a phone soon I'm so broke and this is my only way to conect please help