What do *I* think you should do? I'm not the one insisting everybody is making some kind of unconstrained free choice in a social vacuum. In the context of the society you live in, I think you should continue to rent it out and you would be foolish to do otherwise. Let's not pretend that means you aren't making a profit from that rent, though.
I find it extraordinary that you would own a place worth 20k less than 2007, though. House prices across the board are about 20% higher than mid-2007 (see
this). You have been incredibly unlucky if your place is actually worth less.