Stuck on bootup screen with Apple logo and Spinning Gear

Hey guys, so just recently my mac has been all wierd. A few weeks ago, every time I boot up my computer, theres there apple logo, the spinning gear, and a gray progress bar underneath. I know the progress bar means that it's fixing a problem with the disk. Anyways, sometimes the bar froze at a certain spot, so I had to force shut down and restart it. It took me around 15 tries for the progress bar to work and log in to my account.

Now, the progress bar moves to about a tenth of the way, and then just stops there. A few minutes later, the progress bar dissappears, and the screen's just stuck on the logo and gear. I thought it was working at first, but it wasn't. I gave it 10 minutes, and nothing happened. It was still stuck on the screen. So up until now, I have no solution, so I just keep force shutting it down and restarting it. No success yet.