Looking for a manga about a guy who gets different girlfriends as a result of time travel
Not 100% certain but it sounds a lot like Boku to Kanojo no Koi Log. I've read this one completely (a little short, but still not bad).

The color spread from the first chapter for ease of identification.



Chapter 9 and chapter 13 are where the story restarts with different girl. The protagonist followed his little sister the second time around and failed to save her from disappearing in chapter 12.