I have found the solution. my phone’s battery was loose. so if your phone isn't turning on, take out the battery, make sure your sd and SIM cards are in properly, and put the battery in carefully. after that, it should turn on!
if your phone is stuck like that, it might be because one of your cards are loose (SD, SIM) so just take off the back, take out the battery and check your cards. if they are in properly, carefully and slowly put the battery back in. that may fix it :) that fixed my phone with the same problem