Cardi B Unloads on Offset in Emotional Rant After Split, 'Doing Me Dirty'

Cardi B is unloading on Offset in an emotionally charged video rant amid their nasty split ... calling him out and accusing him of treating her badly.

It's the first time we've seen Cardi get this emotional since she announced she ended things with her estranged husband ... she says he's ungrateful and she's tired of his behavior.

Cardi's pain is coming through clearly here ... it's evident in her voice, as she says she's done a lot for Offset over the years, only for him to play games with her when she's at her most vulnerable. She's also taking shots at him with social media posts.

As we reported ... Cardi announced she was single earlier this month after they both unfollowed each other on social media, revealing they had been broken up for a while before she went public.

There's been plenty of drama and cheating rumors between Cardi and Offset over the years ... but they've split and gotten back together before, and now they have two kids together.

Cardi says she's helped Offset out for years without so much as a "thank you" from him ... and it sounds like he wasn't taking their issues seriously leading up to and after the split, at least from her perspective.