I'm not sure you are correctly identifying the bar at the bottom. The slider bar at the bottom under the back, play/pause, and forward buttons is a volume control slider. You want the slider on the top for the song progress. To get this to show up, you can tap once anywhere on the screen that is not an icon or control feature. I suggest tapping the center of the album artwork.
Now, take a look at my second pic again. If you tapped once on the artwork, you should now have a progress bar towards the top of the screen. On the left, UNDER the progress bar there is a small oval icon of 2 arrows chasing each other. If it is blue, then repeat is on. If it is blue with a circle on the left side that has a 1 in it, then it's set to repeat every song once. If it is white, then repeat is off.
To toggle between each option, you have to tap that oval icon once to get to the next option. So if the icon is just blue, you tap once to get to "repeat one time" and then tap again to turn repeat off.
So, tap the screen anywhere to toggle between seeing the progress bar, and not seeing it. You want to see it.
Then check the oval icon UNDER the bar on the left, and if it is blue, then it is on repeat, and will continue to play the same track over and over. If you tap it, you will then be in "repeat once" mode, where it will repeat every song once. Tap it again and the icon should be white, meaning that repeat has been turned off.