why is my iPhone 7 stuck on the apple logo?

So this all started on Monday 12/03/18 when I received a call from someone and could not hear anything and they say they could not hear anything from my side too; we tried this 7 times back and forth. then another friend called and it was the same thing. I decided to turn my phone off and turn it back on. my phone was stuck on the black screen with the white apple logo for a hour and I was getting scared. I connected it to my Macbook and did a update. everything was successful as my MacBook told me but my phone was still on the black screen with the white apple logo. so I did it again and rested it. the first time I did it, everything was slow, nothing worked properly. I repeated the process until everything was working. on Tuesday 13/03/18 I flied out to Budapest and released I can't take calls still and my camera did not work at all I can't take pictures or videos on the camera app or on snapchat; the only way I could if when ever the app froze I turn the app off and then turn it back on and wish for the best ( so I had a few photos;thank god I had friend that toke photos for me. but now Friday 17/03/18 my phone came out off charge and I put it into charge and its stuck on the black screen with the white apple logo again. now because I have a few picture I don't want to restore my phone again to get it to work. what do I do ?

please help me