Should I talk to my boss directly about how tasks are being handed out by a teammate? 'Cause what happened last night still has me anxious and confused.

I'm 35, office worker in a private company in Khon Kaen, been a coordinator for almost six years. Small team, about ten people, with a department head and a section head. Overall work environment is okay — some coworkers friendly, some quiet — but nobody expected this would happen.

Short version first lol
One teammate in the same department but handling different responsibilities keeps dumping small tasks that aren’t really my job onto me. When I get tired of doing them, they go to the boss and say there’s a problem with overlapping work, but they never talk to me directly. Result: the boss called me out in a meeting even though I raised my hand to explain and wasn't given the chance to speak. I felt so unfairly treated, like seriously WTF.

I'll tell the long version 'cause I'm still asking myself what to do. My role is coordination with many parties — issuing documents, scheduling meetings, coordinating with provincial teams, and maintaining a pretty detailed database. One teammate (let’s call them Poom) handles external coordination with big clients, while I focus on internal stuff and the systems. But Poom often sends files or asks me to check data or set up system settings that are actually Poom's responsibility, claiming urgent meetings or client cases. Sometimes I help because I want the team to keep running smoothly, but it became a regular thing.

Over the past almost two months I felt like toward month-end I was pulled into more and more tasks that aren’t mine. My own deadlines started slipping. I messaged Poom privately like, “Is this yours or mine? Can you tell me ahead if you want my help so I can plan?” Poom replied casually, “Sorry, the client’s pushing,” and then disappeared. Then one day we had a big team meeting after 2 pm; the boss was stressed and called an emergency meeting. Turns out some work missed sending info to a client. The boss said, “This work shows the OP is careless, lacks responsibility,” and looked at me. I was nearly in shock and went silent.

I tried to raise my hand to explain that another party was involved, but the boss didn’t give me a chance. Some nearby teammates stayed quiet and didn’t back me up. I swallowed my feelings and kept calm. After the meeting I talked to the boss privately, gave details that Poom had coordinated several times and that I had said I needed to schedule it. The boss just said, “You’re the one responsible overall; it still has to be done.” That tone locked me into being the one at fault, even though the process was unclear.

After that Poom sent a short apology message but ended with telling me to care more about the client. It felt like getting yelled at in the meeting and then having a coworker lightly rub salt in the wound. It really hurt T_T. I talked to a close friend at the office and they said maybe I didn’t manage my queue well, but they sounded unsure. That made me doubt myself — am I overthinking, or should I admit fault? But in reality I’d asked Poom to handle things many times and they either didn’t reply or sent bits back.

Now I'm really stressed, sleepless for 2–3 nights. One night I sat alone until 1am, mind blank, a small coffee cup left on the desk, and a single yellow post-it on my monitor saying “check before sending.” I just want task distribution to be clear and neutral so no one gets blamed alone, but I'm afraid if I talk to the boss again it'll turn into a fight or the boss will see me as weak and I’ll get exploited. If I talk to Poom directly I’m worried the team vibe will get tense; I don’t want to make it awkward.

So what should I do? Keep it to myself and wait to see if it resolves, or ask for written, clearer task assignments so no one gets singled out? Or am I just making a big deal out of nothing? Sorry if I rambled, it’s just stuck in my head.

Please share ways to handle this without making things worse but also without letting myself get blamed again. I want straight advice.

P.S. This is my first time posting, sorry if I messed up anything.