When Melinda is at her house with her parents, they get up very late to celebrate Christmas because they were sleeping in. Melinda got some gift cards and some other stuff, but the present that made her cry was the sketch pad and charcoal pencils.
This is huge because her parents are realizing that she's interested in drawing and they notice she does it a lot. This causes her to almost tell them about the time last summer when she got raped by Andy Evans.
She starts crying because she can't process it all and she can't communicate with her parents about what happened.