Witj the play controls visible, to the far left, look and see if there is a little 1 visible between two bent arrows all in orange. If so tap it once and the arrows should turn black and the 1 should disappear. That should give you back normal play. It sounds like you have your musicom to repeat one song. I did this the other day on my Mac with Google Play. Took me a while to realize it and find the fix.