Are you able to sit outside for a little while? Have you tried this in the past?

I personally find then when I am like what you describe, sitting outside helps. The natural world and especially plants tend to just look and feel (atmosphere-wise) more peaceful, beautiful and non-threatening.

Being cooped up indoors during that sort of thing tends to make it worse for me. I find that if I can sit outside for a little while with a cigarette and some decaf coffee and just chill, it helps calm me down.

The natural world is still, peaceful, serene. The indoors feels unnatural and I tend to see things more, as far as brief hallucinations and having startle responses.

The indoors will feel like a nightmare during that sort of episode, for me, while the outdoors will just feel kind of dreamy and magical.

That's all I've got as far as short-term suggestions, because it's all that works for me. I do know that getting in that state really sucks, especially if alone and inside.