Mine was doing the same thing. I had not damaged it in any way. At first I was able to get it to catch and it unlocked. Once I got to the home screen it started going crazy and flipping screens (left to right) on its own. The only thing I could think that may have done something was that I used my boyfriend's charger and he mentioned that you cannot use your phone while it is charging. After I remembered that, I plugged my phone in to its own charger and tried again and it worked! I guess maybe something in the charging inlet was hung.
I'm sure by now you have replaced or fixed your problem but I thought I might share for anyone else who comes across this post that has a similar problem