I have a boot loop problem and the power button doesn't work

My phones power button cover fell so I had to use a pencil to turn it on but it kind of destroyed the power button and when I use a USB cable to my computer to turn it on, it turns on for a few seconds but when it gets to the Samsung logo and jingle it turns it off while in the boot logo. I've tried many methods and all result in a boot loop. I really need help please so I can do calls.