Was your weather muggy at the time, by any chance? Was the soil still moist? If you water it every other day, and it looked fine the day before, I am guessing it might have gotten a disease. Perhaps a root rot. Some fungal and bacterial diseases are active in warm, muggy weather.

Was it actually in a basket or a pot? The baskets are better aerated which is the only reason I'm asking.

Usually by the time symptoms show up it's too late (yep, they're that fast). You could try a fungucide and see if it does any good.

Good luck, and I hope for the best. For what it's worth, Triphylla type Fuchsias perform better in your climate. Their ancestor is native to the Caribbean and tolerates hot, humid weather better than most of them.

having lived in houston i know how hot it can be fuchsias like to be moist but dont like having wet feet did you pot have draining holes plastic pots will also boil the roots in realy hot conditions even in the uk it may be better next time to let the pot dry out so the compost is coming away from the edge you could also spray to keep the humidity down