Stuck on booting screen

Hey, I have. Macbook mid-2010. It has the High Sierra OS installed on it. I was trying to do some things for my upcoming Mission Trip on it, but it was being super slow. I restarted my Mac which usually solves the problem, but this time it gave me a new and much bigger problem. I am stuck on the gray booting screen. The loading bar has completely filled, but it will not move on to he next screen. Please help! I have tried holding down command r to get to the disk utility. When I did the first aid it says “the volume Macintosh HD appears to be OK”