Rematch AP too homesick to work

Host family of second AP here. First AP left after 5 months due to personality differences and language barrier. Our second AP (20F) from Mexico seemed super happy to be here, has her own car and gym membership, has friends, and just took a 5 day trip to Chicago to see her boyfriend. When she returned, she has been so depressed she’s unable to leave her bed/room and I’ve been dropping off meals and tea to her room (she told me she was sick - maybe the flu). She didn’t show up for work yesterday so I gave her the day off and watched my daughter. She told us last night she’s so homesick she may go home. Then today, she also wasn’t getting out of bed and I went to her room to get her up because I don’t have any backup childcare and need to work. She said she’ll “try” to work today.

My question is - WTF? She’s been here 3 weeks and things seemed to be going great, we’ve been checking in regularly and include her in all meals and family outings/events. She told me she wants to be closer to her boyfriend, but that’s not really an option. We said he can come visit or family can come visit, offered to get her out of the house to pick up her spirits, but she doesn’t want to do anything but sleep. After just going through rematch 3 weeks ago I don’t have it in me to do again. What do people do in this situation? I’m an attorney and my husband owns a business and we’re both frequently out of the house. I can work from home a few days a week, but it’s hard.

Stay with AP program or go back to a nanny? The worst part is we let go our wonderful nanny for this and it’s just been so difficult.

Edited to update: AP talked to our LCC in person and said it was a reaction to seeing her boyfriend and being sad, and she wants to stay.

However, I’m not sure if I’m confident she is stable enough to be my daughter’s primary caregiver. Ugh.