'Teen Mom's' Catelynn Lowell Reacts To Amber Portwood Losing Custody Of 4-Year-Old Son

Amber Portwood received support from one of her "Teen Mom" co-stars after she lost her three-year legal battle with ex-boyfriend Andrew Glennon over the custody of their son.

This week, an Indiana judge granted Glennon sole legal and primary physical custody of their 4-year-old son James. Portwood expressed her shock over the ruling Thursday via a statement on Instagram, where Catelynn Lowell left a comment defending Portwood.

"I love you. I’m so sorry that this is happening and SO undeserved," Lowell wrote Thursday, according to Us Weekly. "He needs you in his life and what they decided is so wrong on so many levels. YOU [know your] truth and all the hard work you have done. DON'T let ANYONE make you think differently! I’m here for you forever and always."

In her post, Portwood, who also shares 13-year-old Leah with ex Gary Shirley, said that she was "devastated and heartbroken by this outcome" before detailing her efforts to be able to keep James.

"I've worked so hard to better myself and improve my relationship with my children," she wrote. "While I've always been candid about my past substance abuse and issues with mental health, a person should have a chance to redeem themselves and not be tethered to their issues from the past."

She continued, "People who've done therapy and taken classes, and made efforts to change should not continue to be punished for past mistakes. I've spent years rebuilding my bridge and did everything that was required of me, including completing 21 negative drug tests and multiple psychological evaluations."

Portwood's son will be moving from Indiana to California to live with his dad.

According to court documents obtained by The Sun, the judge advised Glennon to "seek out and consider the mother's opinion before making any major decisions relating to the child's medical treatment, education and religion."

Portwood was granted overnight visits with James, beginning at three days each month, the documents stated.

Overnights were introduced to help James adjust to his new schedule, and it will alternate between Indiana and California.

In phase two, her visitation will be upped to five days, and in phase three, there is an undetermined amount of days set forth, with the document noting that "mother will have parenting time pursuant to the Indiana parenting guidelines with distance as a major factor based upon the age of the child."

The judge also ordered both Glennon and Portwood to submit monthly drug tests for the next six months.

An unnamed source told People that the MTV star is now "contemplating what options she has to fight this" and feels frustrated, considering how far she has come.