Britney Spears Says Estrangement From Sons Feels Like 'A Part of Me Has Died'

Britney Spears seems agitated/remorseful/hurt over the estrangement of her 2 sons, and is blaming it on Kevin Federline doing a TV interview.

Britney hopped on social media Saturday and said at one point she had physical custody of her kids more than Kevin -- when they were 6 through 9 years old.  She says she had them 70% of the time.

As we reported, the 2 kids -- 16-year-old Sean Preston and 15-year-old Jayden James -- have not seen their mom going on 6 months, and Britney says, "Since they've been gone I've honestly felt like a huge part of me has died."

This is an about-face from the anger she directed at her kids on social media, calling them "hateful," which triggered backlash.

She also said they were money-grubbing since child support payments were going to stop in a few years ... insinuating that's why they went on TV.

Custody of the 2 children has been a centerpiece of the family conflict. Before the conservatorship was established, a family law just stripped Britney of all custody and gave her supervised visitation conditioned on random drug testing.

Once the conservatorship was created and things became stable, she regained custody and it was about 50/50. Over the years, that began to wane and the kids spent way more time with Kevin than Britney.

Britney went on ... "Like literally I have no purpose anymore -- they were my joy, they were my everything. I look forward to seeing them."