You must not power the HX711 using 5V if the I/O signals are on 3.3V! Connect VCC of the HX711 board to 3.3V (the HX711 works in the range 2.6 - 5.5V). Check if D5 is already fried on the Wemos.
Try to call startLoadcell() after the Wemos woke up. Post the output you get.
You might want to call LoadCell.powerDown() and LoadCell.powerUp() before and after going to sleep.