Los Angeles, Jan 9 (IANS): Singer Madonna is reportedly "at her wit's end" over her estrangement from her 15-year-old son Rocco and her ongoing custody battle with her ex-husband Guy Ritchie.

"She has been crying constantly over what's going on with Rocco," an insider told usmagazine.com. 

The 57-year-old pop star, who said that her children meant the world to her, was completely unhappy with the situation. 

As previously reported, Rocco had expressed "very clearly that he didn't want to return to New York" and decided to stay with his father in London. 

"Rocco is a typical 15-year-old who wants to do what he wants," the insider explained. 

Rocco also said that it's hard for him to stay at Madonna's house without his sister Lourdes, who went away to college in Michigan last year. 

"Rocco misses Lola so it's really hard for him not having her around at Madonna's house," the source added. 

"He is incredibly close to her so it's really hard for him to be alone at his mom's without her." 

Madonna and Guy divorced back in 2008 after eight years of marriage. In 2006, the former couple adopted son David Banda Mwale Ciccone Ritchie from Malawi.