When I'm first aware of the problem, I tell myself, "Stop. Think." Which is kind of a personal signal to try to mentally step back from the situation, look at the problem, and plan out a solution. I can't act without a plan; without a plan I'm just lost and likely to melt down.
That's exactly what you're doing, isn't it? I mean--looking at the problem, solving it, making a plan? Bravo.
To de-fuse potential meltdowns, I:
--Go somewhere private, quiet, and preferably dim.
--Curl up, sit down, lean up against something. Having to maintain my own body posture can get stressful when there is so little energy left.
--Wrap self in blanket, or crawl under a weighted blanket.
--Close eyes, put head down, cover head in some way. This blocks out some sensory input.
--Mentally slow heart rate and breathing, reduce muscle tension. (You can easily learn to do this through relaxation techniques.)
--Wait. Usually, this works. If not, just wait out the meltdown--I'm already in a quiet, relatively private place, so it does less damage there than anywhere else.