It isn't all sunshine and roses

This past Thursday we had one of those really "down" days.  We had taken a sister to another city to get her new dentures. This whole process has taken several trips at about an hours' drive each way. We have taught her countless lessons, taken her to doctor's appointments, and to and from the church ( a 20 minute drive each way) many times since August. We have grown very attached to her, and she is a very spiritual person.  She went to the temple for the first time on December 15th.  We drove her in a snowstorm and didn't get home until after 1 in the morning.  We haven't minded doing all this because that is what missionaries do. However, on Thursday as we were returning to her home, she told us that she has decided to quit coming to the church.  She said she had changed she email address; cancelled her cell phone, and she won't answer a knock on her door.  Writing a letter is our only means of communicating.  For the rest of the evening and the next day I felt absolutely disheartened.  I know she is now vulnerable to temptations, loneliness, and negativity because she has cut herself off from all who care about her, and I am truly sad about that.  I also worry about her salvation because she has made sacred covenants, not to be trifled with.  My returned-missionary children assure me that these feelings are common in missionary life, but even so, I am devastated. I keep praying she will have the strength to come back.