What do you do if your girlfriend keeps walking away from you?

spend more time with her and give her more attention. If you are not being attentive to her needs, your relationship, or are not sharing any feelings with her, being rude or demeaning her in any way these things could tend to push her away or even if your too overbearing, too needy, too controlling or just being clingy these are also reasons you could push her away. Talking with her and finding out exactly why she feels this way would be a good start.