How to fix iPhone if it is jailbroken or has viruses

My iPhone has been acting really weird lately and I have tried everything possible to fix it. It has been very slow and it keeps freezing up. This morning I was on my phone and all of this weird stuff randomly came up it looked almost like when they hack computers in movies it was all white it had words and there was a lot. I have no idea what going on if you have any suggestions please help also I don’t want to reset my phone or anything like that so if you know anything please let me know.