How do I handle what feels like an unbearable amount of emotional pain?

A long series of events has lead to the point I'm at rn. But today has been really really heavy and I feel like I can't breath properly. The sheer amount of emotional pain and grief and anger I feel are distorting my immediate awareness of reality and I can't seem to convince my brain that this will pass and that feelings don't stay one way forever, it's like my subconscious has accepted that this is it, it's game over. How do I stay grounded in reality and not go on a self destruction tangent that will actually kill the chances of things ever getting better? And how do I alleviate even all little bit of the pain I feel right now cause it really is too much, I feel like I'm dying.