It may have been easier to pick up the difference between essere and stare to describe health and feelings because there is a right solution and a wrong solution...but there are some cases in which sometimes you can use stare the way you use essere = when describing location. This is more common in some regions than others...so stick to essere and you can't go wrong.
- L'insalata sta/è sopra il tavolo/The salad is on top of the table
- La stazione sta/è in fondo alla strada/The station is at the end of the street
Probably not. Mi dispiace :) Stare and its various forms are better used to express personal states of being, eg. health, ill-health or just how you are in general = Come stai?
However, I have an interesting discussion going on elsewhere on duolingo that you may be interested in following http://duolingo.com/#/comment/404909