Ay nako, that's scary talaga! Since you're pregnant, I'd really suggest calling your orthodontist right away to let them know what happened, they need to check kung okay lang ang bracket na nawalan at kung kailangan i-replace agad, plus your OB din just to be safe na walang concerns sa baby. A few of my mum friends had small dental emergencies during pregnancy and ang doctors nila were actually super reassuring once they knew, so don't worry too much, most likely okay lang everything, pero better safe than sorry, especially ngayong pregnant ka pa.