Before anything I am sorry if something like this was posted but I can't found...and for my english(it isn't my first language).

I have an JB iPhone 5 16GB with iOS 7.1.4 and I didn't have any problem with it before...but yesterday I did an update on Cydia and later I instaled a new lock screen on my phone. It was all fine with all this.
But today my phone seems ok until I opened the camera. It was weird...the camera screen was black and I wasn't able to use the shot button or go to camera roll. I was able to go out or close the app but when I opened it, was black again and it has the same problem so I restarted my iPhone. But when I did that my phone was stuck in the apple screen but I saw it was in reality blinking(NOT intermittent) if it was in a looping restart, I don't know.
I tried to press the on/off button but nothing happened so I tried to press on/of and home together and it went in off mode. I pressed "on" alone and nothing...pressed "on" and home and it turned on but stuck and blinking again. So again I pressed "on" and home to turn it off and this time I was able to press "on" alone to turn it on but it contiunes to stuck and blinking.
Can someonte help me? I am not even know what is happening...