My daughter is 7 month old and she cries more with me than when she's with anyone else. Why?

Hard to say. This is difficult to determine. She may be starting to test you and she knows that she can push her limits with you more than anyone else. Sometimes babies go through a stage where they prefer one parent over the other, but it passes. Continue to be patient with her and show her that you love her. If it persists, check with your doctor.