Sorry this has happened to you. I can completely understand why you're upset. Dealing with something like this right now myself.

Something that sometimes helps me is a sort of Buddhist technique where you hold still with the feeling - don't think, just the feeling - and neither fight against it nor engage with it. Realize your feelings are a part of your self and try to embrace and comfort yourself as if you were a hurting child.

Eventually, life will lead you into something else like another task that has to be done, and it will help turn your attention elsewhere.

Repeat as often as necessary until the River sweeps the whole sorry episode downstream.